JP2012256599A - Multiple channel light source power supply with output protection function - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a multiple channel light source power supply with an output protection function which may resolve problems with the prior art.SOLUTION: If a current sense output from a current sense circuit 116 exceeds a pre-determined threshold, a controller circuit 114 provides a protection switch 112 with an output for changing the protection switch 112 from a state where an output DCof a front end circuit 102 is coupled to a plurality of voltage converter circuits 106-1, 106-2, ..., 106-N, namely, a conductive state, to a state where the output DCof the front end circuit 102 is decoupled from the plurality of voltage converter circuits 106-1, 106-2, ..., 106-N, namely, a nonconductive state.

Description

This application is a United States entitled “OUTPUT PROTECTION CIRCUIT FOR MULTI-CHANNEL HIGH WATTAGE POWER SUPPLY” filed on June 9, 2011, which is hereby incorporated by reference herein in its entirety. US Patent Application No. 13 / 404,415 filed February 24, 2012 and filed September 21, 2011, claiming priority of provisional patent application 61 / 495,291 This is a continuation-in-part of US Provisional Patent Application No. 61 / 537,562 entitled “MULTI-CHANNEL POWER PROTECTION MOSFET SWITCH”.
The present invention relates to lighting, and more particularly to a lighting power source.

Certain types of power sources used in the United States are regulated by safety standards set forth by the American Insurer Safety Laboratory, particularly those set forth in UL 1310, Class 2. The UL 1310 standard limits the voltage, current and power of each output of a power supply classified as a Class 2 power supply. This limitation needs to be met even under single component failure conditions. For example, power in UL 1310, Class 2 based power supplies is currently limited to 100 watts per output channel. Each channel / output of the power supply has a configuration for driving a separate light source, for example, a solid light source (ie, a light emitting diode (LED), an organic light emitting diode (OELD), etc.), a gas discharge lamp, an incandescent lamp, etc. obtain.
In those power supplies, two voltage conversion stages, that is, a front end stage and an output stage may be used. The front end stage may receive an input voltage, for example, an AC voltage of 120V, and convert the input voltage to a stabilized DC output voltage. The output stage can receive this DC output from the front end stage and provide a stabilized DC output for each channel of the power supply using a DC / DC converter. Thus, each stage can limit output voltage, current, and power.

US Provisional Patent Application No. 61 / 495,291 US Patent Application No. 13 / 404,415 US Provisional Patent Application No. 61 / 537,562

  In a single channel power supply, the front end stage and output stage can both be set to less than 100 watts so that each stage is a backup for each other. In a multi-channel / output power source, a total of 100 watts or more of power can be supplied to each output channel. Therefore, a multi-channel type power supply may need to set the limit output of the front-end stage to 100 watts or more, and therefore cannot be a backup for the possibility of a single component failure in a single channel of the output stage.

  The most influential fault that can occur in a multi-channel / output power supply is a short circuit in adjusting one or more of the outputs (eg, a short in the output buck regulator MOSFET or inductor), which has failed. It can cause a bad output where maximum front end power is delivered to a single channel. This fault is probably not a problem with a single channel / output power supply if the maximum front-end limit output for UL 1310 is less than 100 watts, but if the failed channel is in a multi-channel / output power supply, the front The end stage limit power can be significant, perhaps over 100 watts.

  In one known configuration, the problem that more than 100 watts of power can be delivered from a single failed output channel is solved by adding protection circuitry to each output channel. This protection circuit can monitor the voltage and current of each output channel and can shut down the channel and / or the entire power supply if any value of voltage, current or power is too high. However, since the addition of the protection circuit requires more parts and space, both monetary cost and efficiency cost are added. Alternatively, it goes without saying that the total generated power across all channels of the power supply can be made 100 watts or less.

  According to one aspect of the present invention, a power supply is provided in which a protection circuit is provided between the front end stage and the output stage, and the output stage includes a plurality of voltage conversion circuits. Each voltage conversion circuit provides a separate associated output for each output channel of the power supply. A current detection circuit is connected to the voltage conversion circuit and provides a current detection output to the control circuit. When the passing current in one or more of the voltage conversion circuits exceeds a predetermined value represented by the current detection output, the control circuit provides an output to the protection switch that disconnects the output of the front end stage from the voltage conversion circuit. Therefore, if a short circuit or other malfunction occurs in any of the voltage conversion circuits of the output stage, all the voltage conversion circuits of the output stage are effectively turned “off”, thus overpowering the output power supply channel (eg, over 100 watts or more). ) Is avoided.

  In some aspects, it may be desirable to reduce or eliminate efficiency loss due to resistance losses associated with the current sensing circuit. In those aspects, the current detection circuit may include a current sensor that provides a current detection output and a bypass switch connected in parallel to the current sensor. The bypass switch may be placed in a non-conductive state to determine a short circuit in one or more of the voltage conversion circuits, so that a current representative of the current passing through the voltage conversion circuit flows through the current sensor, and thus the current detection output. Establish. When the current detection output exceeds a predetermined threshold, the control circuit provides an output for disconnecting the front end stage from the voltage conversion circuit to the protection switch. If the current detection output does not exceed the predetermined threshold value, the control circuit connects the output of the front end stage to the voltage conversion circuit, and outputs an output that shunts the current around the current sensor by arranging the bypass switch in a conductive state. Provide protection switch. The shunt current around the current sensor when the voltage conversion circuit is fed by the normal function of the power supply circuit reduces or eliminates a decrease in efficiency due to resistance loss associated with the current sensor.

  Thus, the power supply circuit embodiment provides an output that protects a multi-channel / output power supply without the need to provide additional circuitry for each channel of the power supply. This provides benefits related to size, cost, reliability and efficiency. In addition, the embodiment may include a current detection circuit that provides a current detection output that is a voltage output, thus minimizing additional energy loss. Further, when the voltage conversion circuit is disconnected from the front end stage by the protection switch, the power consumption of the power source can be kept low because the front end stage enters the standby mode.

  According to one aspect, a light source power circuit is provided having a number of output channels. The light source power supply circuit includes a front end circuit configured to receive an input voltage and provide a stabilized front end direct current (DC) output voltage, a plurality of voltage conversion circuits, and each voltage conversion circuit includes the stabilized front end. A plurality of voltage conversion circuits having a configuration that receives a direct current (DC) output voltage and provides a separate associated DC output to an associated one of a number of output channels, between the plurality of voltage conversion circuits and the front end circuit A protection switch coupled to the conductive state connecting the front end direct current (DC) output voltage to the plurality of voltage conversion circuits, and disconnecting the front end direct current (DC) output voltage from the plurality of voltage conversion circuits. A protection switch having a non-conductive state, a current detection circuit connected to the plurality of voltage conversion circuits, a current sensor, and the current sensor A bypass switch connected in parallel, the bypass switch having a conductive state for shunting current around the current sensor and a non-conductive state for passing current through the current sensor, so that the bypass switch comprises: In a non-conductive state, a voltage across the current sensor establishes a current detection output that represents a passing current of at least one voltage conversion circuit of the plurality of voltage conversion circuits, and the protection switch includes the current switch A control circuit having a configuration arranged in a non-conductive state according to the detection output.

  According to a related aspect, the plurality of voltage conversion circuits may include a plurality of switches, and the control circuit causes one switch in the plurality of switches to be placed in a non-conductive state, and thus to the one switch in the plurality of switches. It may be configured so that no power is delivered to the light source connected to the output channel of the associated light source power circuit.

  In another related aspect, a protection switch can be coupled between the low side output of the front end circuit and the plurality of voltage conversion circuits. In yet another related aspect, the plurality of voltage conversion circuits may be a plurality of switching power supply circuits, the current sensor may include at least one resistor, and the at least one resistance may be included in each of the plurality of switching power supply circuits. A passing current of the plurality of switching power supply circuits may be detected by being coupled to the switching power supply circuit, and the current detection output may include a voltage across the at least one resistor. In yet another related aspect, the protection switch may include a gate transistor connected to the controller, a power supply connected to the at least one resistor, and a drain connected to each switching power supply circuit of the plurality of switching power supply circuits. In another related aspect, the drain may be connected to a switch portion of each switching power supply circuit of the plurality of switching power supply circuits via a resistor.

  In yet another related aspect, a protection switch may be coupled between the high side output of the front end circuit and the plurality of voltage conversion circuits. In yet another related aspect, the current sensor may include at least one resistor coupled between the low side output of the front end circuit and ground, and the current sense output may include a voltage across the at least one resistor.

  In another related aspect, each voltage conversion circuit of the plurality of voltage conversion circuits may be configured as a buck converter. In yet another related aspect, the bypass switch can include a transistor.

  According to another related aspect, a multi-channel / output light source power supply circuit is provided. The multi-channel / output type light source power supply circuit includes a front-end circuit having a configuration for receiving an input voltage and providing a stabilized front-end direct current (DC) output voltage, and a plurality of voltage conversion circuits. A plurality of voltage converting circuits configured as a buck converter and configured to receive the stabilized front end direct current (DC) output voltage and provide a separate associated DC output to an associated one of a number of output channels; A protective switch coupled between the plurality of voltage conversion circuits and a low-side output of the front end circuit, a conductive state coupling the front end direct current (DC) output voltage to the plurality of voltage conversion circuits; Protective switch having non-conductive state disconnecting end direct current (DC) output voltage from said plurality of voltage conversion circuits A current detection circuit connected to the plurality of voltage conversion circuits, including a current sensor and a bypass switch connected in parallel to the current sensor, wherein the bypass switch shunts current around the current sensor; A non-conductive state for passing current through the current sensor, and thus when the bypass switch is in a non-conductive state, the voltage across the current sensor is at least one voltage of the plurality of voltage conversion circuits A current detection circuit that establishes a current detection output representative of the current passing through the conversion circuit, and a control that provides an output that places the protection switch in a non-conductive state so that power is not delivered to a light source connected to multiple output channels A control circuit for providing the output in response to the current detection output.

  According to a related aspect, the protection switch may include a transistor having a gate connected to the controller, a power source connected to at least one resistor, and a drain connected to each voltage conversion circuit of the plurality of voltage conversion circuits. In yet another related aspect, the drain may be connected to each voltage conversion circuit of the plurality of voltage conversion circuits via a resistor.

  In another related aspect, the plurality of voltage conversion circuits are a plurality of switching power supply circuits, and the current sensor includes at least one resistor connected to each switching power supply circuit of the plurality of switching power supply circuits. In another related aspect, the bypass switch includes a transistor.

  According to another aspect, a method is provided for protecting one or more output channels of a number of output channel type power supplies from overpowering. The method includes disposing a bypass switch connected in parallel to a current sensor in a non-conductive state, disabling each voltage conversion circuit of the plurality of voltage conversion circuits, wherein the plurality of voltage conversion circuits include the one or more voltage conversion circuits. Preventing power supply to one or more light sources connected to the output channel, detecting current through a current sensor, and current detection representing a passing current of the plurality of voltage conversion circuits after the voltage conversion circuit is disabled Establishing an output, detecting whether the current detection output is equal to or higher than a predetermined level. If the current detection output is higher than the predetermined level, disconnect the front end circuit from the plurality of voltage conversion circuits. The switch is placed in a conductive state to shunt current around the current sensor, thus enabling each voltage conversion circuit of the plurality of voltage conversion circuits to provide one or more output channels. Thereby feeding the one or more light sources connected to include.

  In a related aspect, disabling each voltage conversion circuit of the plurality of voltage conversion circuits may include placing a switch portion of each voltage conversion circuit of the plurality of voltage conversion circuits in a non-conductive state. In other related embodiments, disconnecting the front end circuit from the plurality of voltage conversion circuits may include changing a state of a protection switch coupled between the front end circuit and the plurality of voltage conversion circuits.

  Provided is a light source multi-channel power source with an output protection function that can solve the problems of the conventional apparatus as described in "Problems to be Solved by the Invention".

FIG. 3 is a block diagram of a power supply according to an embodiment of the present invention. FIG. 3 is a circuit diagram of a power supply according to an embodiment of the present invention. FIG. 6 is another circuit block diagram of a power supply according to an embodiment of the present invention. FIG. 3 is a block flow diagram of a method according to an embodiment of the present invention. FIG. 3 is a block diagram of a current detection circuit of a method according to an embodiment of the present invention. FIG. 3 is a circuit diagram of a power supply according to an embodiment of the present invention. FIG. 3 is a block flow diagram of a method according to an embodiment of the present invention.

FIG. 1 shows a schematic block diagram of the power supply circuit 100. The power supply circuit 100 includes a known front end circuit 102 and an output stage 104. The output stage 104 includes associated individual light sources 108-1, 108-2,. . . 108-N, a plurality of voltage conversion circuits 106-1, 106-2,. . . 106 -N and a protection circuit 110. The protection circuit 110 includes a protection switch 112, a control circuit 114, and a current detection circuit 116. The front-end circuit 102 receives the input voltage V _in directly or via a known dimming circuit (not shown), and receives a stabilized DC output DC _reg via the protection circuit 110. 106-2,. . . 106-N. For example, in one embodiment, the input voltage V _in may be an alternating current (AC) input provided directly from 120VAC / 60 Hz supply voltage. However, the system according to each of the embodiments described herein may be operated with, but not limited to, a DC power source or other AC power source that provides 220-240 VAC at 50-60 Hz.

For example, the front-end circuit 102 known rectifier circuit receiving the input voltage V _in, the known switching power supply circuit, a controller for controlling the switches in the switching power supply circuit may incorporate. Various forms of rectifier circuits are known in the art. For example, in some embodiments, the rectifier circuit may include a known diode bridge rectifier or an H-bridge rectifier. The switching power supply circuit receives the rectified AC output from the rectifier and receives a plurality of voltage conversion circuits 106-1, 106-2,. . . 106 -N is provided with a stabilized DC output DC _reg through the protection circuit 110. Various switching power supply configurations are known in the art including, for example, buck converters, boost converters, buck-boost converters, and the like. These devices generally operate selectively, such as transistors that can store energy in an energy storage device, such as an inductor, and then transfer the energy to a load, such as a light source, using one or more filter capacitors. Includes switch. Other known types of switching power supplies include known transformer-based switching power supplies such as "flyback" power supplies. In a transformer-based switching power supply, the primary side of the transformer can be coupled to the rectified AC output of the rectifier. A regulated DC output voltage is provided to a secondary side of the transformer that is electrically isolated from the primary side.

  Various controllers that control the switches of the switching power supply are known. If the switching power supply configuration is, for example, a buck converter, the controller may be a model number TPS40050 controller currently available from Texas Instruments, Dallas, Texas. The switching power supply circuit may also include a known power factor correction (PFC) circuit.

The plurality of voltage conversion circuits 106-1, 106-2,. . . Each of 106-N may include a known switching power supply circuit (and thus a plurality of switching power supply circuits). Each of the plurality of switching power supply circuits may include a switch (and thus a plurality of switches) as described above. The plurality of switching power supply circuits may include a known controller that controls the plurality of switches. The plurality of voltage conversion circuits 106-1, 106-2,. . . 106-N each receive a stabilized DC output DC _reg of front end circuit 102 and associated DC outputs DC _out1 , DC _{out2 ,.} . . DC _outN is _connected to the associated light source 108-1, 108-2,. . . 108-N. The plurality of voltage conversion circuits 106-1, 106-2,. . . 106-N, each associated DC output DC _out1 , DC _{out2 ,.} . . DC _outN is referred to herein as the “channel” or “output” of the power supply circuit 100. Related light sources 108-1, 108-2,. . . 108-N may include any combination of known types of light sources, such as but not limited to incandescent lamps, gas discharge lamps, or solid state light sources. Related light sources 108-1, 108-2,. . . If the light source with 108-N is a solid state light source, the light source may include a group of solid state light sources (eg, multiple LEDs) interconnected in a series and / or parallel configuration.

The plurality of voltage conversion circuits 106-1, 106-2,. . . The passing current of each of the voltage conversion circuits 106 -N can be fed back to the current detection circuit 116 that can provide a current detection output to the control circuit 114. In some embodiments, the current detection circuit 116 may be configured as one or more resistors (shown in FIGS. 2 and 3), and the current detection output may include a plurality of voltage conversion circuits 106-1, 106-2,. . . It may be a voltage across one or more resistors, which represents the passing current of one or more voltage conversion circuits of 106-N. When a current detection output exceeding a predetermined threshold is provided from the current detection circuit 116, the control circuit 114 switches the protection switch 112, and the output DC _reg of the front-end circuit 102 has a plurality of voltage conversion circuits 106-1, 106-2, . . . 106-N (ie, the conductive state), the output DC _reg of the front-end circuit 102 is converted into a plurality of voltage conversion circuits 106-1, 106-2,. . . The protection switch 112 is provided with an output that changes to a state disconnected from 106-N (ie, a non-conductive state).

The protection switch 112 can be any component or group of components that has a conductive or “closed” state and a non-conductive or “open” state. In some embodiments, protection switch 112 includes a transistor. When the protection switch 112 is in a conductive or “closed” state, the output DC _reg of the front end circuit 102 is a plurality of voltage conversion circuits 106-1, 106-2,. . . 106-N and, if non-conductive or “open”, a plurality of voltage conversion circuits 106-1, 106-2,. . . Disconnected from 106-N. The control circuit 114 may have any form of circuit configuration that provides an output that changes the state of the protection switch 112 in response to the current detection output of the current detection circuit 116. For example, the control circuit 114 may be a microcontroller having a configuration that changes the conductive state of the protection switch 112 when the current detection output exceeds a predetermined threshold.

  The plurality of voltage conversion circuits 106-1, 106-2,. . . In the embodiment in which 106-N is configured as a plurality of switching power supply circuits including a plurality of switches, the control circuit 114 includes a plurality of voltage conversion circuits 106-1, 106-2,. . . For each voltage conversion circuit 106-N, the plurality of voltage conversion circuits 106-1, 106-2,. . . 106-N are placed in a non-conductive or “open” state, and a plurality of voltage conversion circuits 106-1, 106-2,. . . Assuming that there is no malfunction in 106-N, the plurality of voltage conversion circuits 106-1, 106-2,. . . 106-N associated light sources 108-1, 108-2,. . . 108-N has a configuration that provides an output that prevents power from being provided. For example, the control circuit 114 disables a gate that drives a transistor switch in one switching power supply in a plurality of switching power supply circuits, thus turning off the switching power supply so that power is not supplied to the associated light source by the transistor switch. It can have a configuration.

In this configuration, the control circuit 114 includes a plurality of voltage conversion circuits 106-1, 106-2,. . . When 106-N is “off” (that is, non-conductive / “open” state), the passing currents of the plurality of switches in the plurality of switching power supply circuits are slightly or zero, and the current detection output of the current detection circuit 116 is a predetermined threshold value. As a result, the conductive state of the protection switch 112 changes. However, for example, the plurality of voltage conversion circuits 106-1, 106-2,. . . When a short circuit occurs at one switch at 106-N, for example, across the transistor switch, the current detection circuit 116 provides the control circuit 114 with a current detection output that exceeds a predetermined threshold. In response to this, the control circuit 114 changes the conductive state of the protection switch 112 and converts the stabilized DC output DC _reg of the front end circuit 102 into a plurality of voltage conversion circuits 106-1, 106-2,. . . Disconnect from 106-N.

  Accordingly, in the power supply circuit 100, the protection circuit 110 includes one or more associated light sources 108-1, 108-2,. . . 108-N may be supplied with excess power, a plurality of voltage conversion circuits 106-1, 106-2,. . . Protects against failure at 106-N. For example, in one embodiment, the component values of the current detection circuit 116 (component values) and the predetermined threshold value set in the control circuit 114 are a plurality of voltage conversion circuits 106-1, 106-2,. . . The plurality of voltage conversion circuits 106-1, 106-2,..., Before one of the 106-N fails and more than 100 W of power is provided to the associated power supply circuit 100 channel. . . 106-N is established to disconnect the front end circuit 102 and thus comply with the UL 1310 Class 2 standard.

  The power source according to the embodiment (also referred to as “power circuit” throughout the specification) may have various configurations. FIG. 2 illustrates a power supply circuit 100a, which includes a front end circuit 102, a protection circuit 110a, and light sources 108a-1,. . . A plurality of voltage conversion circuits 106a-1,... Having a configuration providing associated outputs / channels for driving 108a-N. . . An output stage including 106a-N. In FIG. 2, the associated light sources 108a-1,. . . 108a-N is configured as a plurality of light emitting diodes 202 connected in series. However, any type of light source and / or a separate output / channel that drives a different type of light source for each channel can be used without departing from the scope of the present invention. Related light sources 108a-1,. . . When a solid state light source is included in 108a-N, each solid state light source may include any number of solid state light sources or a single solid state light source coupled in series, parallel, serial parallel combination. The operating characteristics and number of solid state light sources connected to one of the outputs / channels of the power supply circuit according to each embodiment described herein are the operating characteristics and number of solid state light sources connected to the other one of the outputs / channels. Can be different.

In FIG. 2, a plurality of voltage conversion circuits 106a-1,. . . 106a-N is provided in known buck converter configurations. For example, the voltage conversion circuit 106a-1 includes a metal oxide semiconductor field effect transistor (MOSFET) Q2, which acts as a switch, a switch controller 204-1, a resistor R1, a diode D1, and an inductor L1. The power source of the MOSFET Q2 is connected to the low side output of the output DC _reg from the front end circuit 102 via the resistor R1 and the protection circuit 110a, and the drain of the MOSFET Q2 is connected to the high side output of the output DC _reg from the front end circuit 102. And the associated light source 108a-1. The diode D1, the drain of MOSFET Q2, while being connected to the high side output of the output DC _reg from the front end circuit 102, is reverse biased with respect to the high-side output of the output DC _reg from the front-end circuit 102. Switch controller 204-1 is coupled to the gate of MOSFET Q2 to provide pulse width modulation (PWM) of the gate drive signal that opens and closes MOSFET Q2 in a known manner. For example, in one embodiment, switch controller 204-1 may be a model number TPS40050 controller currently available from Texas Instruments, Dallas, Texas.

The plurality of voltage conversion circuits 106a-1,. . . Each voltage conversion circuit in 106a-N may have the same buck converter configuration. For example, the voltage conversion circuit 106a-N includes a metal oxide semiconductor field effect transistor (MOSFET) QN that functions as a switch, a switch controller 204-N, a resistor RN, a diode DN, and an inductor LN. The power source of the MOSFET QN is connected to the low side output of the output DC _reg from the front end circuit 102 via the resistor RN and the protection circuit 110a, and the drain of the MOSFET QN is an inductor to the high side output of the output DC _reg from the front end circuit 102. Connected via LN and associated light sources 108a-N. Diode DN from the drain of MOSFET Qn, is connected to the high side output of the output DC _reg from the front end circuit 102, also, it is reverse biased with respect to the high-side output of the output DC _reg from the front-end circuit 102. Switch controller 204-N is coupled to the gate of MOSFET QN to provide a PWM gate drive signal that opens and closes MOSFET QN in a known manner.

The protection circuit 110a includes a protection switch 112a, a current detection circuit 116a, and a control circuit 114a. In FIG. 2, the protection switch 112a is configured as a MOSFET Q1, and the power source of the MOSFET Q1 is connected to the low-side output of the output DC _reg of the front end circuit 102 via a current detection circuit 116a configured as a resistor R _sense . The drain of the MOSFET Q1 has a plurality of voltage conversion circuits 106a-1,. . . 106a-N, a plurality of switches Q2. . . The resistors R1. . . Connected via RN. In this configuration, the plurality of voltage conversion circuits 106a-1,. . . 106a-N, in particular a plurality of switches Q1. . . QN is connected to the low-side output of the output DC _reg of the front-end circuit 102 via the protection switch 112a and the current detection circuit 116a. Thus, when the protection switch 112a is in a conductive or “closed” (ie, “on”) state, the low-side output of the output DC _reg of the front-end circuit 102 is converted into a plurality of voltage conversion circuits 106a-1,. . . 106a-N, but when the protection switch 112a is in a non-conductive or “open” (ie, “off”) state, a plurality of voltage conversion circuits 106a-1,. . . 106a-N is disconnected, and thus power supply to the output / channel of the power supply circuit 100a is stopped.

The gate of MOSFET Q1 is connected to control circuit 114a and a voltage V _sense across resistance R _sense is provided as an input to control circuit 114a. When the passing current of the resistor R _sense provided as an input to the control circuit 114a, and thus the voltage V _sense exceeds a predetermined level, the plurality of voltage conversion circuits 106a-1,. . . One or more of 106a-N may be shorted or failed. For example, a short circuit across switch Q2 or switch QN may cause excess power to be delivered to the associated output / channel location of power supply circuit 100a. Accordingly, to accommodate that the voltage V _sense exceeds a predetermined level, the control circuit 114a provides an output to the gate of the MOSFET Q1, causing the MOSFET Q1 to be placed in a non-conductive state or an “open” state, and thus the front end circuit 102. Output DC _reg from the plurality of voltage conversion circuits 106a-1,. . . 106a-N, and the power supply to all outputs / channels of the power supply circuit 100a is stopped.

  In FIG. 2, the control circuit 114a includes a plurality of switches Q2. . . Switch controller to QN 204-1. . . The output for enabling or disabling the provision of the 204-N PWM gate drive output is converted into a plurality of voltage conversion circuits 106a-1,. . . 106a-N switch controllers 204-1. . . 204-N. The switch controller 204-1. . . When 204-N is activated, the switch controller 204-1. . . 204-N PWM gate drive output is a plurality of switches Q2. . . QNs are alternately placed in a conductive (“closed”) state and a non-conductive (“open”) state, thus the plurality of switches Q2. . . Associated light source 108a-1. . . Power is supplied to 108a-N. The switch controller 204-1. . . When 204-N is invalidated, these switch controllers 204-1. . . 204-N is a switch Q2. . . Placing the QN in a non-conductive or “open” (ie, “off”) state, thus the associated light source 108a-1. . . Power supply to 108a-N is stopped.

A plurality of voltage conversion circuits 106a-1,... That can cause excessive power supply to the output / channel of the power supply circuit 100a. . . A failure or short circuit in 106a-N may occur from the control circuit 114a to the switch controller 204-1. . . 204-N with a plurality of switches Q2. . . This can be detected by placing the QN in a non-conductive ("open") state and providing an output that stops powering the light source. Multiple switches Q2. . . When QN is placed in a non-conductive state and Q1 is placed in a conductive or “closed” state, a plurality of switches Q2. . . If there is no failure in QN, the current passing through resistor R _sense should be very small. In this situation, the voltage V _sense does not exceed the predetermined value set in the control circuit 114a, and the control circuit 114a maintains the MOSFET Q1 in a conductive or “closed” state with respect to the gate of the MOSFET Q1. The output DC _reg is converted into a plurality of voltage conversion circuits 106a-1,. . . 106a-N continues to provide output to be coupled. Next, the control circuit 114a includes a plurality of switches Q2. . . Enable the gate drive output to the QN and the associated light source 108a-1. . . 108a-N is operated normally and the output for resuming the power supply is supplied to the switch controller 204-1. . . 204-N.

However, a plurality of switches Q2. . . A plurality of voltage conversion circuits 106a-1,..., Such as a short circuit across one or more of QN. . . If one or more of 106a-N fails, a plurality of switches Q2. . . If QN is placed non-conductive state ( "open") state current can pass through the short circuit portion via a MOSFETQ1 and resistor R _sense. This can cause a voltage V _sense exceeding a predetermined value set in the control circuit 114a. On the other hand, the control circuit 114a arranges the MOSFET Q1 in a non-conductive state and converts the output DC _reg of the front end circuit 102 into a plurality of voltage conversion circuits 106a-1,. . . An output can be provided to the gate of MOSFET Q1 that disconnects from 106a-N and thus stops powering the output channel.

  FIG. 3 illustrates a power supply circuit 100b having another configuration. The power supply circuit 100b includes a front end circuit 102, a protection circuit 110b, and an output stage, which includes the associated light sources 108a-1,. . . A plurality of voltage conversion circuits 106a-1,... Each having a configuration providing an associated output / channel driving 108a-N. . . 106a-N. The front end circuit 102 and the plurality of voltage conversion circuits 106a-1,. . . 106a-N, associated light sources 108a-1,. . . 108a-N are the same as those shown and described in connection with power supply circuit 100a in FIG. For simplicity, the front end circuit 102, the plurality of voltage conversion circuits 106a-1,. . . 106a-N, associated light sources 108a-1,. . . The description of 108a-N is not repeated.

In FIG. 3, the protection circuit 110b includes a protection switch 112b, a current detection circuit 116b, and a control circuit 114b. The current detection circuit 116b is configured as a resistor R _sense that couples the low side output of the output DC _reg of the front end circuit 102 to ground through it. Multiple switches Q2. . . The power source of QN is a resistor R1. . . Each is connected to ground via RN.

The protection switch 112b is configured as a MOSFET Q1, and the drain of the MOSFET Q1 is connected to the high-side output of the output DC _reg of the front end circuit 102 via a resistor Ra. The power source of MOSFET Q1 is associated with the associated light source 108a-1,. . . 108a-N and inductor L1, and reverse biased diodes D1. . . A plurality of voltage conversion circuits 106a-1,. . . 106a-N switches Q2. . . It is connected to the drain of each switch in QN. In this configuration, the plurality of voltage conversion circuits 106a-1,. . . 106a-N, in particular a plurality of switches Q2. . . QN is connected to the high-side output of the output DC _reg of the front end circuit 102 via the protection switch 112b and the resistor Ra. Thus, when the protection switch 112b is in a conductive or “closed” state, the high side output of the output DC _reg of the front end circuit 102 is converted into a plurality of voltage conversion circuits 106a-1,. . . 106a-N, but when the protection switch 112b is in a non-conductive or "open" state, the high side output of the output DC _reg of the front end circuit 102 is a plurality of voltage conversion circuits 106a-1,. . . 106a-N is disconnected, and thus power supply to the output / channel of the power supply circuit 100b is stopped.

The power source of the MOSFET Q1 is connected to the collector of the bipolar junction transistor (BJT) 302, and is also connected to the drain of the MOSFET Q1 through the resistor Rb. The emitter of BJT 302 is connected to ground. The base of the BJT 302 is connected to the output of the control circuit 114b via resistors Rc and Rd, and the junction between the resistors Rc and Rd is grounded via a filter capacitor C1. When the passing current of the resistor R _sense (ie, the current detection circuit 116b) provided to the input of the control circuit 114b, and thus the voltage V _sense exceeds a predetermined level, the plurality of voltage conversion circuits 106a-1,. . . One or more of 106a-N may be shorted or failed. Therefore, the control circuit 114b is configured to provide an output for placing the BJT 302 in the conductive state to the gate of the BJT 302 via the resistors Rd and Rc in response to the voltage V _sense exceeding a predetermined level. When the BJT 302 is in a conductive state, the MOSFET Q1 is placed in a non-conductive state or “open” state, and thus the output DC _reg from the front end circuit 102 is converted into a plurality of voltage conversion circuits 106a-1,. . . Disconnect from 106a-N and stop the power supply to the output / channel of the power supply circuit 100b.

  The control circuit 114b includes the switch controller 204-1. . . 204-N to a plurality of switches Q2. . . An output for enabling or disabling provision of PWM gate drive output to QN is provided for each switch controller 204-1. . . 204-N. The switch controller 204-1. . . When 204-N is activated, the switch controller 204-1. . . 204-N PWM gate drive output is a plurality of switches Q2. . . A plurality of switches Q2. . . QNs are alternately placed under a conductive state (“closed”) and a non-conductive state (“open”), and associated light sources 108a-1,. . . Power is delivered to 108a-N. The switch controller 204-1. . . When 204-N is invalidated, the switch controller 204-1. . . 204-N PWM gate drive output is a plurality of switches Q2. . . A plurality of switches Q2. . . QNs are alternately placed under a non-conductive state (“open”) and a conductive state (“closed”), and the associated light source 108a-1,. . . Stop the power delivered to 108a-N.

The plurality of voltage conversion circuits 106a-1,..., Which may cause excessive power supply to the output / channel of the power supply circuit 100b. . . A failure or short circuit in 106a-N may occur from the control circuit 114a to the switch controller 204-1. . . 204-N with a plurality of switches Q2. . . QN is placed in a non-conductive state ("open") state to provide light sources 108a-1,. . . 108a-N can be detected by providing an output that stops power supply to 108a-N. Multiple switches Q2. . . If QN is placed in a non-conductive state and MOSFTETQ1 is placed in a conductive (“closed”) state, the current passing through resistor R _sense should be very small. In this situation, the voltage V _sense does not exceed the predetermined value set in the control circuit 114b, and the control circuit 114b maintains the MOSFET Q1 in the conductive state with respect to the BJT 302 and sets the output DC _reg of the front end circuit 102 to a plurality of voltages. Conversion circuits 106a-1,. . . 106a-N continues to provide output to be coupled. Next, the control circuit 114b includes a plurality of switches Q2. . . By enabling the gate drive output of the QN, the associated light source 108a-1. . . The switch controller 204-1. . . 204-N.

However, a plurality of switches Q2. . . When QN is arranged in a non-conductive state, a plurality of voltage conversion circuits 106a-1,. . . If one or more of 106a-N fails, the current passing through resistor R _sense can be increased compared to the case without failure. As a result, the voltage V _sense may exceed a predetermined set value in the control circuit 114b. In response to this, the control circuit 114b arranges the MOSFET Q1 in a non-conductive state and outputs the output DC _reg of the front end circuit 102 to the plurality of voltage conversion circuits 106a-1. . . A signal to disconnect from 106a-N may be provided to BJT 320, thus de-energizing the output channel.

  FIG. 4 shows one or more output channels in a multi-output channel type power source, such as the power source circuit 100, 100a, 100b, etc. shown in FIGS. A block flow diagram of methods 400 and 600 to protect against overpowering is shown. The illustrated block flow diagram may be illustrated and described as including a particular sequence of steps. However, the step sequence only provides an example of how to start the general functions described here. Each step need not be performed as described unless otherwise noted.

  In method 400, in step 401, each voltage conversion circuit in the plurality of voltage conversion circuits is configured so that the plurality of voltage conversion circuits do not function for powering one or more light sources connected to one or more output channels of the power source. Disable it. In step 402, a current for establishing a current detection output is detected through a plurality of invalidated voltage conversion circuits. In step 403, it is determined whether or not the current detection output exceeds a predetermined level. If the output is higher than the predetermined level, the front end circuit is disconnected from the plurality of voltage conversion circuits in step 404. In some embodiments, disabling the voltage conversion circuit includes placing a switch portion of each voltage conversion circuit in the plurality of voltage conversion circuits in a non-conductive state at step 405. In one embodiment, disconnecting the front end circuit from the plurality of voltage conversion circuits includes changing a state of a protection switch coupled between the front end circuit and the plurality of voltage conversion circuits in step 406.

Referring to FIG. 1, in each embodiment in which the current detection circuit 116 includes one or more resistors, eg, R _sense as shown in FIGS. 2 and 3, the current detection circuit 116 has an operationally associated resistance loss in the power supply circuit 100. Have. The efficiency loss associated with the resistance loss may be unacceptable in certain embodiments and / or applications. In order to reduce or avoid the efficiency drop, the light sources 108a-1,. . . A bypass switch may be provided in the current detection circuit 116 that effectively establishes a short circuit via the current detection circuit 116 during power feeding to 108a-N.

For example, FIG. 5 illustrates a current detection circuit 116 c, which includes a bypass switch 502 and a current sensor 504. The current sensor 504 may be configured as one or more resistors (eg, R _sense shown in FIGS. 2, 3 and 6), and the low-side output of the front end circuit 102 and the plurality of voltage conversion circuits 106-1, 106-2. . . 106-N is connected directly as shown in FIG. 3 or via a protection switch 112a as shown in FIG. As previously described, the voltage V _sense across current sensor 504 can be provided as an input to control circuit 114. When the voltage V _sense exceeds a predetermined value, the plurality of voltage conversion circuits 106a-1,. . . One or more of 106a-N may be shorted or faulted. In order to respond to the voltage V _sense exceeding a predetermined value, the control circuit 114 switches the protection switch 112 and the output DC _reg of the front end circuit 102 to the plurality of voltage conversion circuits 106a-1,. . . 106a-N is arranged to be disconnected from the power supply circuit 100 and configured to provide a signal for stopping power supply to all outputs / channels.

The bypass switch 502 is connected in parallel to the current sensor 504 and receives a bypass control signal from the control circuit 114. Bypass switch 502 can be any component or group of components having a conductive or “closed” state and a non-conductive or “open” state as controlled by a bypass control signal from control circuit 114. For example, in one embodiment, bypass switch 502 can include a transistor. When the bypass switch 502 is in a non-conductive or “open” state (eg, an open circuit), the resistance is so high that the current I _sense passes through the current sensor 504 but not through the bypass switch 502. However, when the bypass switch 502 is in a conductive or “closed” state (eg, a short circuit), the resistance is so small that the current I _sense is shunted around the current sensor 504 and passes through the bypass switch 502. .

Referring back to FIG. 1 together with FIG. 5, in general, when the power of the power supply circuit 100 including the current detection circuit 116c as shown in FIG. 106a-1. . . 106a-N and the light source 108a-1. . . An output may be provided to stop power supply to 108a-N, and a bypass control signal may be provided to bypass switch 502 that places the bypass switch in a non-conductive (or “open”) state. Since the current I _sense flows through the current sensor 504 under the situation where the power supply is stopped and the bypass switch 502 is open, the control circuit 114 detects the voltage V _sense across the current sensor 504 and detects the voltage V _{sense. It} can be determined whether _sense is greater than or _equal to a predetermined threshold. When the voltage V _sense is equal to or higher than a predetermined threshold, the control circuit 114 causes the light sources 108a-1. . . 108a-N continues to provide an output to stop power supply, and the front end circuit 102 is connected to a plurality of voltage conversion circuits 106a-1. . . An output for disconnecting from 106a-N may also be provided to protection switch 112, thus de-energizing all power / channels of power supply circuit 100.

However, if the voltage V _sense does not exceed the predetermined threshold value, the control circuit 114 will control the light sources 108a-1. . . 108a-N, a signal for delivering power to the voltage conversion circuit 106a. . . 106a-N switch controller may also be provided and a bypass control signal may be provided to bypass switch 502 that causes bypass switch 502 to be placed in a conductive (or “closed”) state. In this configuration, current I _sense is shunted around current sensor 504 via bypass switch 502. Thus, the resistance loss associated with the current detection circuit 116c is reduced or eliminated, so that the efficiency is improved compared to a configuration that does not include the bypass switch 502.

A current sensing circuit 116c that includes a bypass switch 502 may again be provided in any embodiment according to the present invention. For example, FIG. 6 shows one embodiment of a power supply circuit 100c that includes a protection circuit 110c shown for illustrative purposes only. The protection circuit 110c includes a current detection circuit 116c, a control circuit 114a, and a protection switch 112a. The current detection circuit 116c includes a current sensor 504a and a bypass switch 502a. Current sensors 504a is configured as a resistor R _sense, the bypass switch 502a is configured as MOSFETQb which parallel connected to the resistor R _sense, i.e., the resistor R _sense is connected between the power source and the drain of MOSFETQb. The gate of MOSFET Qb is connected to control circuit 114a. The control circuit 114a is configured to provide a bypass control signal for changing the conductive state of the MOSFET Qb to the gate of the MOSFET Qb.

The power supply circuit 100c includes a front end circuit 102 and associated light sources 108a-1. . . A plurality of voltage conversion circuits 106a-1,..., Each having a configuration that each provides an associated output / channel for driving 108a-N. . . 106a-N. In general, the front end circuit 102, the protection switch circuit 110c, and the plurality of voltage conversion circuits 106a-1. . . 106a-N, associated light sources 108a-1. . . 108a-N, the bypass switch Qb of the current detection circuit 116c is a light source 108a-1. . . While delivering current to 108a-N, it functions in the same manner as described above in connection with FIG. 2, except that it shunts current I _sense around current sensor R _sense .

In particular, in the embodiment shown in FIG. 6, a plurality of voltage conversion circuits 106a-1... 106 that can cause excessive power supply to the output / channel of the power supply circuit 100c. . . A failure or short circuit in 106a-N may occur from the control circuit 114a to the switch controller 204-1. . . 204-N with a plurality of switches Q2. . . QN is placed in a non-conductive (or “open”) state to provide light sources 108a-1. . . 108a-N can be detected by providing a signal to stop power feeding. The control circuit 114a also provides the bypass switch Qb with a bypass control signal for placing the bypass switch in a non-conductive (or “open”) state. These output from the control circuit 114a, in only when an increase in power supply circuit 100c, for example, the time immediately after the front-end circuit 102 is applied to _{V in,} or one or more times during the operation of the power supply circuit 100c, for example, regular Can be provided at intervals. Bypass switch Qb and a plurality of switches Q2. . . When QN is placed in a non-conductive state and Q1 is in a conductive (“closed”) state, a plurality of switches Q2. . . If there is no failure in QN, the current passing through resistor R _sense should be very small.

In this situation, the voltage V _sense does not exceed the preset value in the control circuit 114a, and the control circuit 114a causes the MOSFET Q1 to output the output DC _reg of the front end circuit 102 to the plurality of voltage conversion circuits 106a-1. . . Continue to provide an output to the gate of MOSFET Q1 that maintains a conductive ("closed") state coupled to 106a-N. The control circuit 114a includes a plurality of switches Q2. . . Enable gate drive output to QN and associated light source 108a-1. . . The outputs that enable normal operation and power supply of 108a-N are also included in the switch controller 204-1. . . 204-N. In addition, the control circuit 114a places the MOSFET Qb in a conductive state and shunts the current I _sense around the resistor R _sense and through the MOSFET Qb, thereby reducing the efficiency based on the resistance loss associated with the resistor R _sense. A bypass control signal to be reduced or avoided is provided to the gate of MOSFET Qb.

However, for example, a plurality of switches Q2. . . A plurality of voltage conversion circuits 106a-1,..., Such as a short circuit across one or more of QN. . . When a short circuit occurs across one or more of 106a-N, a plurality of switches Q2. . . If one or more of QN are placed in a non-conductive ("open") state, current I _sense can pass through the short circuit, MOSFET Q1, and resistor R _sense , and MOSFET Qb is a bypass control signal from control circuit 114a. Is held open. In this situation, the voltage V _sense may exceed a predetermined set voltage in the control circuit 114a. On the other hand, the control circuit 114a arranges the MOSFET Q1 in a non-conductive state, and converts the output DC _reg of the front end circuit 102 into a plurality of voltage conversion circuits 106a-1. . . A signal may be provided to MOSFET Q1 that disconnects from 106a-N and thus stops powering the output channel.

  FIG. 7 shows one or more of the multi-output channel type power supplies, such as the power supply circuits 100, 100a, 100b, 100c, etc. shown in FIGS. A block flow diagram of a method 700 for protecting the output channels of a multi-output channel power supply from overpowering is shown. The illustrated block flow diagram may be illustrated and described as including a particular sequence of steps. However, the step sequence only provides an example of how to start the general functions described here. Each step need not be performed as described unless otherwise indicated.

  In method 700, in step 701, a bypass switch connected in parallel to a current sensor is placed in a non-conductive state. In step 702, each voltage conversion circuit of the plurality of voltage conversion circuits is disabled, and thus the plurality of voltage conversion circuits do not function to power one or more light sources connected to one or more output channels. In one embodiment, to disable the voltage conversion circuit, in step 707, the switch portion of each voltage conversion circuit of the plurality of voltage conversion circuits is placed in a non-conductive state. In step 703, the current passing through the current sensor is detected, and a current detection output representing the invalidated current passing through the plurality of voltage conversion circuits is established. In step 704, it is determined whether the current detection output is equal to or higher than a predetermined level. If the current detection output is equal to or higher than the predetermined level, the front end circuit is disconnected from the plurality of voltage conversion circuits in step 705. In one embodiment, step 708 changes the state of the protection switch coupled between the front end circuit and the plurality of voltage conversion circuits. If the current detection output does not exceed the predetermined level, in step 706, the bypass switch is placed in a conductive state to shunt the current around the current sensor, enabling each voltage conversion circuit in the plurality of voltage conversion circuits, The plurality of voltage conversion circuits are operative to supply power to one or more light sources connected to one or more output channels.

  The methods and systems described herein are not limited to specific hardware or software, but can be applied to many computing or processing environments. The method and system may be initiated in hardware or software, or a combination thereof. It is to be understood that the method and system can be initiated in one or more computer programs, which can include one or more processor executable instructions. One or more computer programs may be executed on one or more programmable processors, one or more protective media (including volatile and non-volatile memory and / or storage elements) readable by the processors, one It can be stored on the above input devices and / or one or more output devices. Thus, the processor can access one or more input devices to obtain input data and can access one or more output devices to communicate with the output data. Input and / or output devices are: Random Access Memory (RAM), Redundant Array of Independent Disks (RAID), Floppy (R) Drive, CD, DVD, Magnetic Disk, Internal Hard Drive, External Hard Drive, Memory Stick Or any other storage device accessible by the processor provided herein, and the embodiments described above are not exhaustive and are intended to be illustrative and not limiting. It is not something.

  The computer program or programs may be initiated using one or more high-level procedural or object-oriented programming languages for communicating with the computer system, if desired, in the assembly or computer language. You can start. The language can be compiled or interpreted.

  Thus, the present invention may embed one or more processors into one or more devices that can operate individually or with each other in a network environment, such as a local area network (LAN), a wide area network ( WAN) and / or intranets and / or the Internet and / or other networks. The network or networks can be wired or wireless, or a combination thereof, and can facilitate communication between different processors using one or more communication protocols. Each processor may have a configuration for distributed processing, and in some embodiments may be a client-server model as needed. Thus, the method and system of the present invention may use multiple processors and / or processor devices, and instructions from the processors may be divided among those single or multiple processors and devices.

  One or more devices or computer systems integrated into one or more processors include, for example, one or more personal computers, workstations (eg, from Sun, HP), personal digital assistance (one or more). PDA), cell phone or smartphone, laptop, handheld device, handheld computer, or other device or devices that may be integrated with the processor or processors described herein. Accordingly, each device described herein is illustrative rather than comprehensive and is not intended to be limiting.

  “A certain microprocessor” and “processor” or “the microprocessor” and “the processor” can communicate with each other in a stand-alone and / or one or more distributed environments, and thus can perform wired or wireless communication with other processors. And the one or more processors may have a configuration that operates on one or more processor controlled devices, which may be similar or different devices. Thus, the terms “microprocessor” and “processor” refer to the use of a central processing unit, arithmetic logic unit, application specific integrated circuit (IC) and / or task engine to illustrate exemplary and non-limiting examples thereof. Shall be included.

  Also, a memory may include one or more memory elements that are readable and accessible by a processor and / or internal and external components of a processor control device, and / or wired or wireless using various communication protocols, unless otherwise specified. Unless otherwise specified, it can be configured to include a combination of external and internal memory devices, and can be continuous and / or divided depending on the application. Thus, references to databases may include commercially available database products (eg, SQL, Informix, Oracle) and proprietary databases, as well as other exemplary and non-limiting examples for associated memory. It may also contain structures such as links, queues, graphs, trees, which are examples.

  A network may include one or more intranets and / or the Internet unless otherwise specified. As used herein, microprocessor instructions or microprocessor executable instructions include programmable hardware.

  “Substantially”, unless otherwise specified, does not substantially affect the clear relationship, state, configuration, orientation and / or other characteristics and methods and systems disclosed herein as understood by those skilled in the art. The deviation shall be included.

106-1. . . 106-N Voltage conversion circuit 106a-1. . . 106a-N Voltage conversion circuit 204-1. . . 204-N Switch controller 108a-1. . . 108a-N light source 100 power supply circuit 100a power supply circuit 100b power supply circuit 100c power supply circuit 102 front end circuit 104 output stage 110 protection circuit 110a protection circuit 110b protection circuit 110c protection circuit 112 protection switch 112a protection switch 112b protection switch 114 control circuit 114a control circuit 114b Control circuit 116 Current detection circuit 116a Current detection circuit 116c Current detection circuit 116b Current detection circuit 202 Light emitting diode 502 Bypass switch 502a Bypass switch 504 Current sensor 504a Current sensor

Claims (15)

A power source circuit for a light source having a number of output channels,
A front-end circuit having a configuration that receives an input voltage and provides a stabilized front-end direct current (DC) output voltage;
A plurality of voltage conversion circuits, each voltage conversion circuit receiving said stabilized front-end direct current (DC) output voltage and providing a separate associated DC output to an associated one of a number of output channels; Multiple voltage converters,
A protective switch connected between the plurality of voltage conversion circuits and the front end circuit, and a conductive state for connecting the front end direct current (DC) output voltage to the plurality of voltage conversion circuits, and the front end direct current ( DC) a protective switch having a non-conductive state disconnecting the output voltage from the plurality of voltage conversion circuits;
A current detection circuit connected to the plurality of voltage conversion circuits, including a current sensor and a bypass switch connected in parallel to the current sensor, wherein the bypass switch shunts current around the current sensor And a non-conductive state that allows current to pass through the current sensor, and thus when the bypass switch is in the non-conductive state, the voltage across the current sensor is at least one of the plurality of voltage conversion circuits A current detection circuit that establishes a current detection output representing the passing current of the voltage conversion circuit;
A control circuit having a configuration in which the protection switch is arranged in a non-conductive state according to the current detection output;
A power supply circuit for a light source.   The plurality of voltage conversion circuits include a plurality of switches, and the control circuit places a switch in the plurality of switches under a non-conductive state, and thus depending on the certain switch in the plurality of switches, the certain switch The power source circuit for a light source according to claim 1, wherein no power is delivered to the light source connected to the output channel of the power source circuit for the light source related to.   The light source power supply circuit according to claim 1, wherein the protection switch is connected between a low output side of the front end circuit and a plurality of voltage conversion circuits.   The plurality of voltage conversion circuits are a plurality of switching power supply circuits, the current sensor includes at least one resistor, and the at least one resistor is connected to each switching power supply circuit of the plurality of switching power supply circuits. The power supply circuit for a light source according to claim 3, wherein a passing current of the power supply circuit is detected.   5. The light source power supply circuit according to claim 4, wherein the protection switch includes a gate transistor connected to a controller, a power supply connected to the at least one resistor, and a drain connected to each switching power supply circuit of the plurality of switching power supply circuits. 6. The light source power supply circuit according to claim 5, wherein the drain is connected to a switch portion of each switching power supply circuit of the plurality of switching power supply circuits via a resistor.   The light source power supply circuit according to claim 1, wherein the protection switch is connected between a high-side output of a front-end circuit and a plurality of voltage conversion circuits.   8. The light source power circuit according to claim 7, wherein the current sensor includes at least one resistor connected between the low-side output of the front end circuit and ground.   The light source power supply circuit according to claim 1, wherein the bypass switch includes a transistor. A power supply circuit for a light source of multi-channel / output type,
A front-end circuit having a configuration for providing a stabilized front-end direct current (DC) output voltage in response to an input voltage;
A plurality of voltage conversion circuits, each voltage conversion circuit being configured as a buck converter and receiving the stabilized front end direct current (DC) output voltage and a separate associated DC output for an associated one of the multiple output channels A plurality of voltage conversion circuits having a configuration to provide
A protective switch connected between the plurality of voltage conversion circuits and a low-side output of the front end circuit, a conductive state connecting the front end direct current (DC) output voltage to the plurality of voltage conversion circuits, and the front end A non-conductive state that disconnects a direct current (DC) output voltage from the plurality of voltage conversion circuits;
A current detection circuit connected to the plurality of voltage conversion circuits, including a current sensor and a bypass switch connected in parallel to the current sensor, wherein the bypass switch shunts current around the current sensor And a non-conductive state that allows current to pass through the current sensor, and thus when the bypass switch is in the non-conductive state, the voltage across the current sensor is at least one voltage of the plurality of voltage conversion circuits A current detection circuit that establishes a current detection output representing the passing current of the conversion circuit;
A control circuit having a configuration for providing an output for disposing the protection switch in a non-conductive state so that power is not delivered to a light source connected to a plurality of output channels, and providing the output according to the current detection output Control circuit,
A power supply circuit for a light source.   The light source power supply circuit according to claim 10, wherein the plurality of voltage conversion circuits are a plurality of switching power supply circuits, and the current sensor includes at least one resistor connected to each switching power supply circuit of the plurality of switching power supply circuits.   The light source power supply circuit according to claim 11, wherein the bypass switch includes a transistor. A method of protecting one or more output channels of a number of output channel type power supplies from excessive power supply comprising:
Placing a bypass switch in parallel with the current sensor in a non-conductive state;
Disabling each voltage conversion circuit of the plurality of voltage conversion circuits so that the plurality of voltage conversion circuits do not supply power to one or more light sources connected to the one or more output channels;
Detecting a current via a current sensor and establishing a current detection output representing a passing current of the plurality of voltage conversion circuits after the voltage conversion circuit is disabled;
It is detected whether or not the current detection output is equal to or higher than a predetermined level. If the current detection output is equal to or higher than the predetermined level, the front end circuit is disconnected from the plurality of voltage conversion circuits. Arranged to shunt current around the current sensor, thus enabling each voltage conversion circuit of the plurality of voltage conversion circuits to supply power to one or more light sources connected to one or more output channels;
Including methods.   The method of claim 13, wherein disabling each voltage conversion circuit of the plurality of voltage conversion circuits includes placing a switch portion of each voltage conversion circuit of the plurality of voltage conversion circuits under a non-conductive state.   14. The method of claim 13, wherein disconnecting a front end circuit from the plurality of voltage conversion circuits includes changing a protection switch state coupled between the front end circuit and the plurality of voltage conversion circuits.

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