TWI668553B - Switching circuit with temperature compensation mechanism and regulator using the same - Google Patents

Abstract

A switching circuit with a temperature compensation mechanism and a regulator using the same. The switch circuit with temperature compensation mechanism includes a main switch circuit and a temperature compensation circuit. The main switch circuit is configured to receive the control signal and generate and output the switch signal when the voltage of the control signal reaches the trigger voltage of the main switch circuit. The temperature compensation circuit is coupled to the main switch circuit. The temperature compensation circuit is configured to adjust the current of the control signal in response to changes in the ambient temperature to temperature compensate the trigger voltage.

Description

Switch circuit with temperature compensation mechanism and regulator using the same

The present invention relates to a switching circuit, and more particularly to a switching circuit having a temperature compensation mechanism and a regulator using the same.

In general, ambient temperature can have a significant impact on the performance of electronic devices. For example, although the electronic device can operate normally when the ambient temperature is room temperature (or normal temperature), when the ambient temperature changes (for example, when it rises to a high temperature or falls to a low temperature), the semiconductor component in the electronic device ( For example, the characteristics of a transistor or a diode will also change. In particular, the current or voltage of the semiconductor component may drift as the ambient temperature changes, causing the operation of the electronic device to change as the ambient temperature changes. Severe cases can even cause the electronic device to be inoperable or out of control.

Furthermore, the interface turn-on voltage of the PN junction of a common transistor (or diode) is a negative temperature coefficient. That is to say, when the ambient temperature is higher, the above-mentioned interface on-voltage is lower, and vice versa. Therefore, when the above transistor is used as a switch, the interface conduction voltage of the PN junction of the transistor switch decreases as the ambient temperature becomes higher, and the effective conduction time interval of the transistor switch changes with the change of the ambient temperature. . If this transistor switch is applied to the vehicle regulator to control the vehicle generator, the operation of the vehicle generator will change with the ambient temperature. In severe cases, the vehicle generator will be unstable and even Not working properly.

In view of this, the present invention provides a switching circuit with a temperature compensation mechanism and a regulator using the same, which can effectively improve the influence of ambient temperature changes on the switching circuit and the regulator, so as to operate the switching circuit and the regulator. more stable.

The switch circuit with temperature compensation mechanism of the present invention comprises a main switch circuit and a temperature compensation circuit. The main switch circuit is configured to receive the control signal and generate and output the switch signal when the voltage of the control signal reaches the trigger voltage of the main switch circuit. The temperature compensation circuit is coupled to the main switch circuit. The temperature compensation circuit is configured to adjust the current of the control signal in response to changes in the ambient temperature to temperature compensate the trigger voltage.

In an embodiment of the invention, the trigger voltage before compensation is a negative temperature coefficient voltage, and the temperature compensation circuit is a positive temperature coefficient current mirror circuit.

In an embodiment of the invention, the main switch circuit includes a diode, a resistor, a transistor, and a bias circuit. The anode end of the diode is used to receive a control signal. The cathode end of the diode is coupled to a temperature compensation circuit. The resistor is coupled between the cathode end of the diode and the ground. The first end of the transistor is used to generate a switching signal. The second end of the transistor is coupled to the ground. The control end of the transistor is coupled to the cathode end of the diode. The bias circuit is coupled between the power terminal and the first end of the transistor. The trigger voltage is the sum of the forward voltage of the diode and the threshold voltage of the transistor.

In an embodiment of the invention, when the diode and the transistor are turned on in response to the control signal, the temperature compensation circuit generates a compensation current to increase the current flowing through the diode, wherein the compensation current is a positive temperature coefficient current. .

In an embodiment of the invention, the temperature compensation circuit increases the compensation current in response to an increase in ambient temperature to increase the forward voltage of the diode. Alternatively, the temperature compensation circuit reacts to a decrease in ambient temperature to reduce the compensation current to reduce the forward voltage of the diode.

The regulator of the present invention is used to control an automotive alternator. The regulator includes a switching circuit with a temperature compensation mechanism. The switch circuit with the temperature compensation mechanism is coupled to the rotor coil of the automotive alternator. The switch circuit with temperature compensation mechanism includes a main switch circuit and a temperature compensation circuit. The main switch circuit is configured to receive the control signal and generate and output a switch signal when the voltage of the control signal reaches the trigger voltage of the main switch circuit to control the current flowing through the rotor coil. The temperature compensation circuit is coupled to the main switch circuit for adjusting the current of the control signal in response to a change in the ambient temperature to temperature compensate the trigger voltage.

Based on the above, in the switch circuit with the temperature compensation mechanism and the regulator using the switch circuit, the temperature compensation circuit can adjust the current of the control signal in response to the change of the ambient temperature to trigger the main switch circuit. The voltage is temperature compensated to reduce the effect of ambient temperature changes on this trigger voltage. In this way, the timing of the switching signal generated by the main switching circuit can be prevented from changing due to the change of the ambient temperature, so that the influence of the environmental temperature change on the switching circuit and the regulator can be effectively improved, so that the operation of the switching circuit and the regulator can be improved. more stable.

The above described features and advantages of the invention will be apparent from the following description.

In order to make the content of the present invention easier to understand, the following specific embodiments are examples of the invention that can be implemented. In addition, wherever possible, the same reference numerals in the FIGS.

Please refer to FIG. 1 . FIG. 1 is a block diagram of a switch circuit with a temperature compensation mechanism according to an embodiment of the invention. The switching circuit 100 having a temperature compensation mechanism may include the main switching circuit 120 and the temperature compensation circuit 140, but the present invention is not limited thereto. The main switch circuit 120 can receive the control signal CS. The main switch circuit 120 can generate and output a switch signal WS when the voltage of the control signal CS reaches the trigger voltage of the main switch circuit 120 to control other circuits or electronic (or motor) devices.

The temperature compensation circuit 140 is coupled to the main switch circuit 120. The temperature compensation circuit 140 can adjust the current of the control signal CS in response to the change of the ambient temperature to temperature compensate the trigger voltage of the main switch circuit 120, thereby reducing the influence of the temperature change on the trigger voltage, wherein the ambient temperature is The temperature of the environment in which the switching circuit 100 is located. In this way, the timing of the switching signal WS can be prevented from changing due to changes in the ambient temperature, so that the purpose of accurately controlling the timing of the switching signal WS can be achieved.

In an embodiment of the invention, the trigger voltage before compensation of the main switch circuit 120 is a negative temperature coefficient voltage, and the temperature compensation circuit 140 is a current mirror circuit with a positive temperature coefficient. In detail, when the ambient temperature rises, the trigger voltage before the compensation of the main switch circuit 120 decreases, and the current generated by the temperature compensation circuit 140 rises to compensate the trigger voltage so that the trigger voltage is approximate. Zero temperature coefficient of voltage.

Please refer to FIG. 2 . FIG. 2 is a schematic diagram showing the circuit structure of the main switch circuit and the temperature compensation circuit according to an embodiment of the invention, which can be applied to the switch circuit 100 with the temperature compensation mechanism of FIG. 1 . The main switch circuit 220 includes a diode 221, a resistor 222, a transistor 223, and a bias circuit 224, but is not limited thereto. The anode end of the diode 221 is for receiving the control signal CS. The cathode end of the diode 221 is coupled to the temperature compensation circuit 240. The resistor 222 is coupled between the cathode end of the diode 221 and the ground GND. The first end of the transistor 223 is used to generate a switching signal WS. The second end of the transistor 223 is coupled to the ground GND. The control end of the transistor 223 is coupled to the cathode end of the diode 221. The bias circuit 224 is coupled between the power terminal VDD and the first end of the transistor 223 to bias the transistor 223. Since the diode 221 and the transistor 223 form a double PN junction, the trigger voltage of the main switch circuit 220 is the sum of the forward voltage of the diode 221 and the threshold voltage of the transistor 223. .

As shown in FIG. 2, the temperature compensation circuit 240 may be a current mirror circuit, but the invention is not limited thereto. The temperature compensation circuit 240 may include the transistors 241, 242 and the reference current source 243, but is not limited thereto. The reference current source 243 is coupled between the power supply terminal VDD and the first end of the transistor 241 for providing a reference current Ir. The first end of the transistor 241 is coupled to the control end and coupled to the control end of the transistor 242. The second end of the transistor 241 and the second end of the transistor 242 are coupled to the ground GND. The first end of the transistor 242 is coupled to the cathode end of the diode 221. In an embodiment of the invention, the temperature compensation circuit 240 can also be implemented with other types of current mirror circuits, and the present invention does not limit the type of current mirror circuit.

In an embodiment of the invention, the bias circuit 224 can be a bias current source, but the invention is not limited thereto. In an embodiment of the invention, the transistors 223, 241, and 242 can be implemented by using an NPN-type Bipolar Junction Transistor (BJT), but the invention is not limited thereto. In other embodiments of the invention, the transistors 223, 241, 242 can also be implemented using a Metal-Oxide-Semiconductor Field-Effect Transistor (MOSFET). The operation of the main switch circuit 220 and the temperature compensation circuit 240 of FIG. 2 will be described below.

When the voltage of the control signal CS is at a logic low level, the diode 221 is in an off state, and the voltage Vb of the control terminal (ie, the base terminal) of the transistor 223 is transmitted through the resistor 222 to be the potential of the ground GND (which is a logic low level). Therefore, the transistor 223 is in an off state, causing the voltage of the switching signal WS to be the potential of the power supply terminal VDD (which is a logic high level). The voltage Vb based on the control terminal (i.e., the base terminal) of the transistor 223 is at a logic low level, at which time the transistor 242 in the temperature compensation circuit 240 will not generate the compensation current Ic.

When the voltage of the control signal CS rises from the logic low level to be greater than or equal to the trigger voltage of the main switch circuit 220 (ie, the sum of the forward voltage of the diode 221 and the threshold voltage of the transistor 223), the diode 221 and the electricity The crystal 223 can be turned on, causing the voltage of the switching signal WS to be the potential of the ground GND (which is a logic low level). At this time, the transistor 242 in the temperature compensation circuit 240 will mirror the compensation current Ic according to the reference current Ir to increase the current flowing through the diode (that is, the current of the control signal CS), wherein the compensation current Ic is Positive temperature coefficient current.

Further, the temperature compensation circuit 240 can increase the current amount of the compensation current Ic in response to an increase in the ambient temperature, so that the forward voltage of the diode 221 rises in response to the increase of the compensation current Ic to compensate the diode 221. Since the forward voltage and the threshold voltage of the transistor 223 are lowered due to an increase in the ambient temperature, it is possible to prevent the trigger voltage of the main switch circuit 220 from changing due to an increase in the ambient temperature. In addition, the temperature compensation circuit 240 can reduce the current amount of the compensation current Ic in response to the decrease in the ambient temperature, causing the forward voltage of the diode 221 to decrease in response to the decrease of the compensation current Ic to compensate the forward voltage of the diode 221 . Since the threshold voltage of the transistor 223 is increased by the decrease in the ambient temperature, it is possible to prevent the trigger voltage of the main switch circuit 220 from changing due to a drop in the ambient temperature. It can be understood that the trigger voltage of the main switch circuit 220 can be a voltage of approximately zero temperature coefficient after being compensated by the temperature compensation circuit 240. In this way, the influence of the ambient temperature factor on the timing of the switching signal WS can be effectively reduced.

Please refer to FIG. 2 and FIG. 3 together. FIG. 3 is a timing diagram of the switching signal WS generated by the main switch circuit 220 of FIG. 2 under different conditions. The voltage Vd_th0 and the waveform W0 are respectively the trigger voltage of the main switch circuit 220 at room temperature and the generated switching signal WS, and the voltage Vd_th1 and the waveform W1 are respectively the trigger voltage of the main switch circuit 220 after temperature compensation at a high temperature. The generated switching signal WS, and the voltage Vd_th2 and the waveform W2 are respectively the trigger voltage of the main switching circuit 220 that is not temperature-compensated at a high temperature and the generated switching signal WS. According to FIG. 3, the timing of the switching signal WS (ie, waveform W2) generated without temperature compensation at a high temperature is larger than the timing of the switching signal WS (ie, waveform W0) generated at room temperature, and is relatively large. The difference between the timing of the switching signal WS (ie, waveform W1) generated by temperature compensation at a high temperature and the timing of the switching signal WS (ie, waveform W0) generated at room temperature is small, so the temperature compensation of FIG. 2 Circuit 240 does effectively reduce the effect of ambient temperature factors on the timing of switching signal WS.

Please refer to FIG. 4, which is a block diagram of a regulator according to an embodiment of the invention. Regulator 40 can be used to control automotive alternator 900. The regulator 40 may include a switching circuit 400 having a temperature compensation mechanism, but is not limited thereto. The switch circuit 400 is coupled to the rotor coil of the automotive alternator 900. The switch circuit 400 may include a main switch circuit 420 and a temperature compensation circuit 440, but the present invention is not limited thereto. The main switch circuit 420 can receive the control signal CS. The main switch circuit 420 can generate and output a switch signal WS when the voltage of the control signal CS reaches the trigger voltage of the main switch circuit 420 to control the current flowing through the rotor coil and control the rotational speed of the automotive alternator 900.

The temperature compensation circuit 440 is coupled to the main switch circuit 420. The temperature compensation circuit 440 can indirectly adjust the current of the control signal CS in response to a change in the ambient temperature to temperature compensate the trigger voltage of the main switch circuit 420, thereby reducing the influence of the ambient temperature change on the trigger voltage and reducing the ambient temperature factor. The effect on the timing of the switching signal WS. In this way, the operation of the vehicle generator (for example, switching) can be prevented from being changed due to the ambient temperature, so that the stability of the vehicle generator can be effectively improved.

In addition, other implementation details and operations of the main switch circuit 420 and the temperature compensation circuit 440 of FIG. 4 are similar to the main switch circuit 120 and the temperature compensation circuit 140 of FIG. 1, respectively, so that the relevant descriptions of FIG. 1 to FIG. 3 above may be referred to. This will not be repeated here.

In summary, in the switch circuit with the temperature compensation mechanism and the regulator using the switch circuit, the temperature compensation circuit can indirectly adjust the current of the control signal in response to the change of the ambient temperature, The temperature of the trigger voltage of the main switch circuit is compensated to reduce the influence of the ambient temperature change on the trigger voltage. In this way, the timing of the switching signal generated by the main switching circuit can be prevented from changing due to the change of the ambient temperature, so that the influence of the environmental temperature change on the switching circuit and the regulator can be effectively improved, so that the operation of the switching circuit and the regulator can be improved. more stable.

Although the present invention has been disclosed in the above embodiments, it is not intended to limit the present invention, and any one of ordinary skill in the art can make some changes and refinements without departing from the spirit and scope of the present invention. The scope of the invention is defined by the scope of the appended claims.

100,400‧‧‧Switching circuit with temperature compensation mechanism

120, 220, 420‧‧‧ main switch circuit

140, 240, 440‧‧‧ temperature compensation circuit

221‧‧ ‧ diode

222‧‧‧resistance

223, 241, 242‧‧‧ transistors

224‧‧‧bias circuit

243‧‧‧Reference current source

40‧‧‧Regulator

900‧‧‧Car alternator

CS‧‧‧Control signal

GND‧‧‧ ground terminal

Ic‧‧‧Compensation current

Ir‧‧‧reference current

W0, W1, W2‧‧‧ waveform

WS‧‧‧ switching signal

V b, Vd_th0, Vd_th1, Vd_th2‧‧‧ voltage

VDD‧‧‧ power terminal

The following drawings are a part of the specification of the invention, and illustrate the embodiments of the invention FIG. 1 is a block diagram of a switch circuit with a temperature compensation mechanism according to an embodiment of the invention. FIG. 2 is a schematic diagram of a circuit structure of a main switch circuit and a temperature compensation circuit according to an embodiment of the invention. 3 is a timing diagram showing the switching signals generated by the main switch circuit of FIG. 2 under different conditions. 4 is a block diagram of a regulator according to an embodiment of the invention.

Claims (10)

A switch circuit with a temperature compensation mechanism, comprising: a main switch circuit for receiving a control signal, and generating and outputting a switch signal when a voltage of the control signal reaches a trigger voltage of the main switch circuit; and a temperature The compensation circuit is coupled to the main switch circuit for adjusting the current of the control signal in response to a change in ambient temperature to perform temperature compensation on the trigger voltage. The switch circuit with temperature compensation mechanism according to claim 1, wherein the trigger voltage before compensation is a negative temperature coefficient voltage, and the temperature compensation circuit is a positive temperature coefficient current mirror circuit. The switch circuit with temperature compensation mechanism according to claim 1, wherein the main switch circuit comprises: a diode, an anode end of the diode is configured to receive the control signal, and the diode is a cathode end coupled to the temperature compensation circuit; a resistor coupled between the cathode end of the diode and a ground; a transistor, the first end of the transistor is used to generate the switch signal, the a second end of the crystal is coupled to the ground end, and a control end of the transistor is coupled to the cathode end of the diode; and a bias circuit coupled to the power supply end and the first end of the transistor Between the terminals, wherein the trigger voltage is the sum of the forward voltage of the diode and the threshold voltage of the transistor. The switching circuit with temperature compensation mechanism according to claim 3, wherein: when the diode and the transistor are turned on in response to the control signal, the temperature compensation circuit generates a compensation current to increase A current flowing through the diode, wherein the compensation current is a positive temperature coefficient current. The switch circuit with temperature compensation mechanism according to claim 4, wherein: the temperature compensation circuit increases the compensation current in response to an increase in ambient temperature to increase the forward voltage of the diode; or The temperature compensation circuit reduces the compensation current in response to a drop in ambient temperature to reduce the forward voltage of the diode. A regulator for controlling a vehicle alternator includes: a temperature compensation mechanism switch circuit coupled to a rotor coil of the vehicle alternator, wherein the temperature compensation mechanism switch circuit comprises: a main switch circuit for receiving a control signal, and generating and outputting a switch signal to control a current flowing through the rotor coil when a voltage of the control signal reaches a trigger voltage of the main switch circuit; and a temperature compensation circuit The main switch circuit is coupled to adjust a current of the control signal in response to a change in ambient temperature to perform temperature compensation on the trigger voltage. The regulator of claim 6, wherein the trigger voltage before compensation is a negative temperature coefficient voltage, and the temperature compensation circuit is a positive temperature coefficient current mirror circuit. The regulator of claim 6, wherein the main switch circuit comprises: a diode, an anode end of the diode is configured to receive the control signal, and a cathode end of the diode is coupled to the a temperature compensation circuit; a resistor coupled between the cathode end of the diode and a ground; a transistor, the first end of the transistor is used to generate the switching signal, the second end of the transistor The ground end is coupled to the ground end, and the control end of the transistor is coupled to the cathode end of the diode; and a bias circuit coupled between the power terminal and the first end of the transistor, wherein The trigger voltage is the sum of the forward voltage of the diode and the threshold voltage of the transistor. The regulator of claim 8, wherein: when the diode and the transistor are turned on in response to the control signal, the temperature compensation circuit generates a compensation current to increase flow through the diode The current of the body, wherein the compensation current is a positive temperature coefficient current. The regulator of claim 9, wherein: the temperature compensation circuit increases the compensation current in response to an increase in ambient temperature to increase the forward voltage of the diode; or the temperature compensation circuit reacts The compensation current is reduced in a temperature environment to reduce the forward voltage of the diode.