JP2013183533A - Power supply device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a power supply device that is capable of minimizing a power loss of an auxiliary power supply part, which performs voltage supply to a drive control part of the power supply device, with a simple construction.SOLUTION: A power supply device includes: a power conversion part 13 for power-converting electric power supplied from an AC power supply 10; an output detection part 14 for detecting an electric variable of a DC electric power supplied to a load 15; a drive control part 17 for controlling driving of the power conversion part 13 on the basis of a result of the detection by the output detection part 14; and an auxiliary power supply part 16 for supplying an electric power to the drive control part 17. At the auxiliary power supply part 16, when auxiliary electric powers having mutually different voltage values are supplied from a first auxiliary power supply path and a second auxiliary power supply path connected to the power conversion part 13, if the voltage value corresponding to the second auxiliary power supply path is lower than a predetermined threshold value given in advance, the first auxiliary power supply path corresponding to the voltage value larger than the predetermined threshold value is selected and the auxiliary electric power supplied from the first auxiliary power supply path is outputted.

Description

  The present invention relates to a power supply device including an auxiliary power supply unit that supplies a voltage to a drive control unit of the power supply device.

  Generally, a power supply device is provided with various drive control functions (drive control units) in order to satisfy various required specifications according to the application. In order for the drive control unit to perform a control operation, it is necessary to supply power to the drive control unit. There are various power supply methods. One method is to configure an auxiliary power supply to supply power.

  For example, in the switching power supply disclosed in Patent Document 1, as an auxiliary power supply, the forward voltage between the ends of the tertiary winding of the flyback transformer or the intermediate tap is switched according to the power supply voltage (intermediate tap voltage). A configuration for supplying power to the internal control circuit has been proposed. The auxiliary power source includes a supply control transistor and a Zener diode that keeps the base voltage of the transistor at a fixed value or less in a path for supplying a forward voltage between both ends of the tertiary winding. The configuration of the series regulator.

  In addition, in the AC adapter disclosed in Patent Document 2, a control power source that forms a control power source based on the output of the third winding of the transformer as an auxiliary power source for the switching control unit, and a transformer power source in a no-load power supply state A configuration including an auxiliary power supply unit that forms an auxiliary power supply equal to or higher than the minimum operating voltage of the switching control unit based on the output of the fourth winding has been proposed. Note that the specific configuration of the auxiliary power supply unit includes a regulator unit that rectifies and smoothes the output of the fourth winding, a power supply control transistor, and a base voltage of the transistor that is lower than the control voltage until a no-load power supply state is reached. This is a configuration of a series regulator including a Zener diode that holds a voltage.

  As described above, the techniques disclosed in Patent Document 1 and Patent Document 2 stabilize the main output system based on load fluctuations and the like, and the voltage of the auxiliary output system for supplying auxiliary power that fluctuates with load fluctuations and the like. In order to achieve stabilization, a configuration is adopted in which a series regulator is placed in the auxiliary power supply.

JP 2011-155773 A JP 2010-068638 A

  However, when the drive control unit (particularly the drive control IC) has a certain power supply voltage tolerance, the voltage stabilization function disclosed in Patent Document 1 and Patent Document 2 is not necessary. From the viewpoint of improving the efficiency of the power supply device, there is a situation in which a configuration in which a series regulator is premised on power loss is not preferable.

  The present invention has been made in view of the above circumstances, and can minimize power loss of an auxiliary power supply unit that supplies voltage to a drive control unit of a power supply device with a simple configuration. It is an object to provide a power supply device.

  In order to solve the above-mentioned problem, the present invention is connected to an AC power source, and converts a power supplied from the AC power source into a predetermined power for a load and performs power conversion, and An output detection unit that detects an electrical variable of DC power supplied to the load, a drive control unit that controls driving of the power conversion unit based on a detection result of the output detection unit, and power for the drive control unit An auxiliary power supply unit that supplies auxiliary power having different voltage values from at least two or more auxiliary power supply paths connected to the power conversion unit. A predetermined threshold is given in advance to the auxiliary power of the auxiliary power supply path, and when the voltage value of one auxiliary power supply path falls below the predetermined threshold, one of the other auxiliary power supply paths is selected. And outputting the auxiliary electric power supplied from the selected route.

  According to the present invention, the power loss of the auxiliary power supply unit that supplies voltage to the drive control unit of the power supply device can be minimized with a simple configuration.

It is a block diagram of the power supply device which concerns on one Embodiment of this invention. It is the block diagram which illustrated the circuit structure of the auxiliary power supply part in the power supply device of embodiment.

  Hereinafter, embodiments of a power supply device of the present invention will be described in detail with reference to the drawings.

  In FIG. 1, the power supply device 1 according to the present embodiment includes an AC power supply 10, an input filter unit 11, a rectification unit 12, a power conversion unit 13, an output detection unit 14, an auxiliary power supply unit 16, and a drive control unit 17. The voltage VO is applied to the load 15.

  Here, the power conversion unit 13 performs power conversion so that the power supplied from the AC power supply 10 is converted into a predetermined DC power and supplied to the load 15. In the configuration of FIG. 1, noise from the AC power supply 10 is removed by the input filter unit 11, converted to DC power by the rectifier unit 12, and then the power factor is improved by the power conversion unit 13 to load 15 side. However, the present invention is not limited to such a configuration. For example, power after rectifying AC power may be supplied to an active filter or the like to improve the power factor. Further, the power conversion unit 13 may include the functions of the input filter unit 11 and the rectification unit 12. Furthermore, the structure which does not have the function of a power factor improvement may be sufficient.

  Further, the output detection unit 14 detects an electrical variable of DC power supplied to the load 15. That is, electrical variables such as the output voltage value VO and the output current value IO (or load current value IL) are detected from the output of the power conversion unit 13 and output to the drive control unit 17.

  Further, the drive control unit 17 controls the drive of the power conversion unit 13 based on the detection result of the output detection unit 14. Specifically, when the power supply device 1 of the present embodiment is a switching power supply device, based on the detection result of the electrical variable input from the output detection unit 14, the drive control of the switching element normally included in the power conversion unit 13 is performed. To do. The configuration of the drive control unit 17 is not particularly limited, but here, control means such as a drive control IC (Integrated Circuit) and a microcomputer are included. Further, the present invention is not limited to the drive control based on the detection result of the output detection unit 14, and may have a function of detecting the current and voltage on the input side (as viewed from the load 15 side) and reflecting it in the drive control. .

  The auxiliary power supply unit 16 supplies power to the drive control unit 17. That is, the auxiliary power supply unit 16 supplies auxiliary power having different voltage values from at least two or more auxiliary power supply paths connected to the power conversion unit 13, and auxiliary power of the two or more auxiliary power supply paths. When a predetermined threshold value is given in advance and the voltage value of one auxiliary power supply path is lower than the predetermined threshold value, one of the other auxiliary power supply paths is selected and the auxiliary power supplied from the selected path Is output.

  FIG. 2 illustrates a specific circuit configuration of the auxiliary power supply unit 16 in the power supply device of the present embodiment. In the figure, the power conversion unit 13 includes a drive unit 131 and a transformer (T1) 132. That is, the power switched by the switching element of the drive unit 131 is supplied to the primary winding W1 of the transformer 132, and the power induced in the secondary winding W2 of the transformer 132 is supplied to the load 15 side. It does not matter whether the transformer 132 and the power supply device 1 (that is, the switching power supply device 1) are insulated or non-insulated.

  The auxiliary power supply unit 16 includes a first rectifier circuit 163, a detection unit 161, and a switching unit 162, and supplies the auxiliary power having different voltage values from the first and second auxiliary power supply paths to the drive control unit 17. The power induced in the tertiary winding (auxiliary winding) W3 of the transformer 132 is used as the auxiliary power for the two auxiliary power supply paths. That is, the first auxiliary power (first output voltage VP1) is supplied from the first terminal P1 of the tertiary winding W3 to the first auxiliary power supply path, and the second auxiliary power is supplied from the second terminal P2 of the tertiary winding W3. The second auxiliary power (second output voltage VP2) is supplied to the supply path.

  Here, the first rectifier circuit 163 is configured in the first auxiliary power supply path, and includes a diode D2 and a capacitor C2, and rectifies and smoothes the first auxiliary power (first output voltage VP1).

  The detection unit 161 is connected to the second auxiliary power supply path, and detects whether or not the value of the second output voltage VP2 of the second auxiliary power is lower than a second threshold value corresponding to the second auxiliary power. The detection result is output. Here, the detection unit 161 includes a second rectifier circuit including a diode D3 and a capacitor C3, a Zener diode D4, and resistors R2 and R3. The Zener diode D4 corresponds to the first switching element described in the claims, and is turned off when the voltage value (second output voltage VP2) of the second auxiliary power supply path is lower than a predetermined threshold value.

  In the detector 161, the anode of the diode D3 is connected to the second terminal P2 of the auxiliary winding W3, and the cathode is connected to the cathode of the Zener diode D4 and one terminal of the capacitor C3. The anode of the Zener diode D4 is connected to one side of the series circuit of the resistors R2 and R3, and the capacitor C3 is connected in parallel to the series circuit of the Zener diode D4 and the resistors R2 and R3.

  The switching unit 162 is configured to extend over the first auxiliary power supply path and the second auxiliary power supply path, and when the voltage value is lower than the predetermined threshold value in the detection unit 161, the voltage value larger than the predetermined threshold value is set. The auxiliary power supply path (that is, the first auxiliary power supply path) is switched to be selected, and the auxiliary power supplied from the first auxiliary power supply path is output.

  The switching unit 162 includes a field effect transistor (hereinafter abbreviated as FET) Q1, a diode D1, resistors R1 and R4, and transistors Q2 and Q3. Here, the FET Q1 corresponds to the second switching element in the claims, is disposed in the first auxiliary power supply path having a voltage value larger than a predetermined threshold value, and is in the on state when the Zener diode D4 is in the off state. Otherwise, it is off. The diode D1 prevents a backflow from the first auxiliary power supply path to the second auxiliary power supply path.

  In the switching unit 162, the base electrode of the transistor Q2 is connected to the connection point between the resistors R2 and R3, and the base electrode of the transistor Q3 is connected to the connection point between the resistor R4 and the collector electrode of the transistor Q2. The gate electrode of the FET Q1 is connected to the collector electrode of the transistor Q3, and the resistor R1 is connected between the source electrode and the gate electrode. Further, the anode of the diode D1 is connected to the second terminal P2 of the auxiliary winding W3, and the cathode is connected to one terminal of the capacitor C1.

  Next, the operation of the auxiliary power supply unit 16 in the power supply device of the present embodiment having the circuit configuration described above will be described. In the following description, the state in which the second auxiliary power (second output voltage VP2) is supplied from the second auxiliary power supply path of the auxiliary power supply unit 16 to the drive control unit 17 is referred to as the second state (normal operation). State), the second output voltage VP2 decreases for some reason and falls below the second threshold value corresponding to the second auxiliary power, and the drive control unit 17 receives the first auxiliary power supply path of the auxiliary power supply unit 16 from the first auxiliary power supply path. A state in which the first auxiliary power (first output voltage VP1) is supplied is defined as a first state (operating state after switching).

  First, in the second state (normal operation state), the second output voltage VP2 output to the second terminal P2 of the auxiliary winding W3 of the transformer 132 is rectified and rectified by a rectifier circuit including a diode D1 and a capacitor C1. The signal is smoothed and supplied to the drive control unit 17 as a DC voltage Vcont.

  At this time, in the second auxiliary power supply path, the second output voltage VP2 output to the second terminal P2 of the auxiliary winding W3 of the transformer 132 is rectified by the second rectifier circuit including the diode D3 and the capacitor C3. After being smoothed, a direct current is supplied to the series circuit of the Zener diode D4 and the resistors R2 and R3. As a result, a voltage corresponding to the supplied direct current and the resistance value of the resistor R3 is generated at both ends of the resistor R3. Actually, since the connection point of the resistors R2 and R3 is connected to the base terminal of the transistor Q2, the base-emitter voltage (Vbe2) of the transistor Q2 appears at both ends of the resistor R3.

  Thus, in a state where the base-emitter voltage (Vbe2) of the transistor Q2 appears at both ends of the resistor R3, the transistor Q2 is turned on, and a direct current is supplied to the transistor Q2 via the resistor R4. At this time, the collector terminal of the transistor Q2 is substantially at the ground potential (Low level). At this time, the base terminal of the transistor Q3 connected to the collector terminal of the transistor Q2 is substantially at the ground potential (Low level), and the transistor Q3 is turned off.

  On the other hand, in the first auxiliary power supply path, the first output voltage VP1 output to the first terminal P1 of the auxiliary winding W3 of the transformer 132 is rectified by the first rectifier circuit 163 including the diode D2 and the capacitor C2. It is smooth. However, the FET Q1 disposed on the first auxiliary power supply path is turned off because the transistor Q3 is turned off, and the DC voltage obtained by rectifying and smoothing the first output voltage VP1 is the diode D1 and the capacitor C1. It will not be supplied to the connection point.

  Next, when the second output voltage VP2 output to the second terminal P2 of the auxiliary winding W3 of the transformer 132 decreases due to some factor, the second auxiliary power supply path includes the diode D3 and the capacitor C3. The DC voltage rectified and smoothed by the two rectifier circuits is also reduced. When this DC voltage falls below the second threshold value, the DC current supplied to the series circuit of the Zener diode D4 and the resistors R2 and R3 decreases, and finally the Zener diode D4 is turned off and the DC current to the series circuit is reduced. The current supply is stopped.

  The state where no DC current is supplied to the series circuit of the Zener diode D4 and the resistors R2 and R3 is a state where no current is supplied to the base terminal of the transistor Q2, and the transistor Q2 is turned off. As a result, substantially all of the direct current supplied via the resistor R4 is supplied to the transistor Q3, and the transistor Q3 is turned on.

  On the other hand, in the first auxiliary power supply path, the first output voltage VP1 output to the first terminal P1 of the auxiliary winding W3 of the transformer 132 is rectified by the first rectifier circuit 163 including the diode D2 and the capacitor C2. It is smooth. The FET Q1 disposed on the first auxiliary power supply path is turned on because the transistor Q3 is turned on, and a DC voltage obtained by rectifying and smoothing the first output voltage VP1 is generated between the diode D1 and the capacitor C1. It will be supplied to the connection point.

  At this time, the first output voltage VP1 is equal to the first output voltage VP1 output to the first terminal P1 of the auxiliary winding W3 of the transformer 132 and the second output voltage VP2 output to the second terminal P2. Since the auxiliary winding W3 is configured to have a high value, the first auxiliary power supply path is interrupted by the diode D1, and the second output voltage VP2 is not supplied to the connection point between the diode D1 and the capacitor C1. It becomes.

  As described above, in the power supply device 1 according to the present embodiment, the power is connected to the AC power supply 10 so that the power supplied from the AC power supply 10 is converted into predetermined DC power and supplied to the load 15. A power conversion unit 13 that performs conversion, an output detection unit 14 that detects an electrical variable of DC power supplied to the load 15, and a drive control unit that controls driving of the power conversion unit 13 based on the detection result of the output detection unit 14 17 and an auxiliary power supply unit 16 that supplies electric power to the drive control unit 17. The auxiliary power supply unit 16 includes first and second auxiliary power supply paths connected to the power conversion unit 13. When supplying auxiliary power having different voltage values, when the voltage value of the second auxiliary power supply path is lower than a predetermined threshold given in advance, the first auxiliary power supply having a voltage value larger than the predetermined threshold Route Selected, it outputs the auxiliary power supplied from the auxiliary power supply path of the first.

  In addition, the auxiliary power supply unit 16 includes a detection unit 161 that detects whether or not the voltage value of the auxiliary power supplied by the auxiliary power supply unit 16 falls below a predetermined threshold in the second auxiliary power supply path. When the voltage value of the second auxiliary power supply path falls below a predetermined threshold, the first auxiliary power supply path is switched to be selected, and auxiliary power supplied from the selected first auxiliary power supply path is output. The switching unit 162 is provided between the first auxiliary power supply path and the second auxiliary power supply path.

  The detection unit 161 includes a first switching element (zener diode D4) that is turned off when the voltage value of the second auxiliary power supply path is lower than a predetermined threshold, and the switching unit 162 includes the first auxiliary element. The second auxiliary power supply from the first auxiliary power supply path and the second switching element (FETQ1) which is arranged in the power supply path and is in the on state when the first switching element is in the off state and is otherwise in the off state. And a diode (D1) that prevents backflow to the path.

  With such a configuration, the second switching element (FET Q1) is turned on when the second auxiliary power decreases due to some factor in the normal operation state and the voltage value of the second auxiliary power supply path falls below a predetermined threshold. The operation state is switched from the operation state in which the second auxiliary power (second output voltage VP2) is supplied to the operation state in which the first auxiliary power (first output voltage VP1) is supplied. Power is supplied. As a result, the operation of the drive control unit 17 is performed in the case of performing a sudden load change, an input voltage change and a drive control for responding to this, or a transient control at the time of starting or stopping the switching power supply device. It is possible to avoid a decrease in the power supply voltage of the drive control unit 17 which is one factor that hinders.

  Further, when the drive control unit 17 (particularly the drive control IC) has a certain power supply voltage tolerance, the voltage stabilization function that causes power loss as disclosed in the prior art is not required. The configuration of this embodiment is sufficient. Therefore, the power loss of the auxiliary power supply unit 16 that supplies voltage to the drive control unit 17 of the power supply device 1 can be minimized with a simple configuration.

  Furthermore, in the power supply device 1 according to the present embodiment described above, the number of auxiliary power supply paths is 2, but when the number of auxiliary power supply paths is N (N is an integer of 2 or more), the following It can be configured as a general form.

  That is, the auxiliary power supply unit 16 supplies auxiliary power having different voltage values from at least N (N is an integer of 2 or more) auxiliary power supply paths connected to the power conversion unit 13, and the N pieces A predetermined threshold value is given in advance to the auxiliary power of the auxiliary power supply path of the first, and the auxiliary power supplied from the kth (k = 2 to N) auxiliary power supply path is supplied from the k-1th auxiliary power supply path. And when the voltage value of the kth auxiliary power supply path is below a predetermined threshold, the k-1th auxiliary power supply path is selected, and the selected k-1th auxiliary power is selected. Auxiliary power supplied from the supply path is output.

  In addition, the auxiliary power supply unit 16 includes a kth detection unit that detects whether or not the voltage value of the auxiliary power supplied by the kth auxiliary power supply path is below a predetermined threshold value in the kth auxiliary power supply path. And when the voltage value of the k-th auxiliary power supply path is lower than the predetermined threshold, the k-1th auxiliary power supply path is switched and the k-1th auxiliary power supply path is selected. The k-th switching unit that outputs the auxiliary power supplied from is provided between the k-th auxiliary power supply path and the k-1th auxiliary power supply path.

  The kth detection unit includes a first switching element that is turned off when the voltage value of the kth auxiliary power supply path is lower than the predetermined threshold, and the kth switching unit has the first switching element turned off. The second switching element that is turned on when it is in the state and outputs auxiliary power supplied from the kth auxiliary power supply path, and is otherwise in the off state, and other auxiliary power from the kth auxiliary power supply path A diode that prevents backflow into the power supply path

  Even in such a general configuration, when the k-th auxiliary power decreases due to some factor in a normal operation state and the voltage value of the k-th auxiliary power supply path is lower than a predetermined threshold, the k-th detection unit The second switching element is turned on to switch from the operating state in which the kth auxiliary power is supplied to the operating state in which the k-1 auxiliary power is supplied, and power is supplied to the drive control unit 17. It will be. As a result, the operation of the drive control unit 17 is performed in the case of performing a sudden load change, an input voltage change and a drive control for responding to this, or a transient control at the time of starting or stopping the switching power supply device. It is possible to avoid a decrease in the power supply voltage of the drive control unit 17 which is one factor that hinders.

  As mentioned above, although embodiment of this invention and its general form were explained in full detail with reference to drawings, this invention is not limited to these embodiment and its general form, The design of the range which does not deviate from the summary of this invention Any changes and the like are included in the present invention. For example, regarding the capacitors C1 to C3 of the embodiment, there is no problem even if these are configured using polar capacitors.

DESCRIPTION OF SYMBOLS 1 Power supply device 10 AC power supply 11 Input filter part 12 Rectification part 13 Power conversion part 14 Output detection part 15 Load 16 Auxiliary power supply part 17 Drive control part 131 Drive part 132 (T1) Transformer W1 Primary winding W2 Secondary winding W3 Tertiary winding (auxiliary winding)
161 detection unit 162 switching unit D1 to D3 diode D4 Zener diode (first switching element)
Q1 FET (second switching element)
Q2, Q3 transistor R1-R4 resistance

Claims (7)

A power converter that is connected to an AC power source and performs power conversion so as to convert the power supplied from the AC power source into a predetermined power for the load; and
An output detector for detecting an electrical variable of DC power supplied to the load;
A drive control unit that controls driving of the power conversion unit based on a detection result of the output detection unit;
An auxiliary power supply unit that supplies power to the drive control unit,
The auxiliary power supply unit supplies auxiliary power having different voltage values from at least two or more auxiliary power supply paths connected to the power conversion unit, and has a predetermined threshold for the auxiliary power of the auxiliary power supply path in advance. When the voltage value of one auxiliary power supply path is lower than the predetermined threshold value, it selects any of the other auxiliary power supply paths and outputs the auxiliary power supplied from the selected path. A featured power supply. The auxiliary power supply unit is
A detection unit for detecting whether the voltage value of the auxiliary power is below the predetermined threshold;
When the voltage value of the auxiliary power is lower than the predetermined threshold value, the auxiliary power supply path is switched to select one of the auxiliary power supply paths having a voltage value larger than the predetermined threshold value, and supplied from the selected auxiliary power supply path. A switching unit for outputting auxiliary power,
The power supply device according to claim 1, comprising: When the auxiliary power supply unit has first and second auxiliary power supply paths,
The detection unit includes a first switching element that is turned off when a voltage value of the second auxiliary power supply path is lower than the predetermined threshold,
The switching unit is in an on state when the first switching element is in an off state, outputs auxiliary power supplied from the first auxiliary power supply path, and is otherwise in an off state; The power supply device according to claim 2, further comprising: a diode that prevents backflow from the first auxiliary power supply path to the second auxiliary power supply path.   The auxiliary power supply unit supplies auxiliary power having different voltage values from at least N (N is an integer of 2 or more) auxiliary power supply paths connected to the power conversion unit, and the N auxiliary power supply units. A predetermined threshold is given in advance to the auxiliary power of the power supply path, and the auxiliary power supplied from the kth (k = 2 to N) auxiliary power supply path is supplied from the k−1th auxiliary power supply path. When it is set smaller than the auxiliary power and the voltage value of the kth auxiliary power supply path is lower than the predetermined threshold, the k-1th auxiliary power supply path is selected, and the selected k-1th auxiliary power supply is selected. The power supply apparatus according to claim 1, wherein auxiliary power supplied from the path is output. The auxiliary power supply unit is
A k-th detector that detects whether the voltage value of the auxiliary power supplied by the k-th auxiliary power supply path is below the predetermined threshold;
When the voltage value of the kth auxiliary power supply path is lower than the predetermined threshold, the k-1th auxiliary power supply path is switched to be selected and supplied from the selected k-1th auxiliary power supply path. A k-th switching unit that outputs auxiliary power to be output;
The power supply device according to claim 4, further comprising: The k-th detection unit includes a first switching element that is turned off when a voltage value of a k-th auxiliary power supply path is lower than the predetermined threshold;
The k-th switching unit is turned on when the first switching element is in the off state, outputs auxiliary power supplied from the k-th auxiliary power supply path, and is otherwise in the off state. And a diode that prevents backflow from the kth auxiliary power supply path to another auxiliary power supply path. The power conversion unit has a transformer,
The power supply apparatus according to any one of claims 1 to 6, wherein auxiliary power for the auxiliary power supply path is supplied from an auxiliary winding of the transformer.

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