JP2021114845A - Current detector and power supply device - Google Patents

Abstract

To detect an input voltage value in high accuracy with a simple configuration.SOLUTION: A voltage detector for detecting an input voltage of a power supply device includes: a transformer; a switching circuit having a plurality of switching elements connected between a first power supply line and a second power supply line, and connected to the primary side coil of the transformer; a rectification part for rectifying an AC signal outputted from the secondary side coil of the transformer; a power supply control part for controlling the switching of the switching circuit; a voltage detection part for detecting a voltage outputted from one end of the secondary side coil of the transformer as an input voltage; and a detection control part for adjusting detection timing of the voltage detection part so that the voltage detection part detects a voltage at the midpoint in a period during which a switching element becomes on-state, the switching element among the plurality of switching elements in the switching circuit conducting the primary side coil between the first power supply line and the second power supply line.SELECTED DRAWING: Figure 1

Description

The present invention relates to a voltage detection device and a power supply device.

Some conventional power supply devices determine whether the input voltage is overvoltage or undervoltage. In such a power supply device, an overvoltage or an undervoltage of the input voltage is determined by using a comparator.

Japanese Unexamined Patent Publication No. 57-09098

However, in the conventional power supply device, the overvoltage, the undervoltage, and the like of the input voltage are determined, and the analog value of the input voltage is not detected. Therefore, it is difficult for a conventional power supply device to respond to fluctuations in output voltage due to sudden changes in input voltage, for example.

The present invention has been made to solve the above problems, and an object of the present invention is to provide a voltage detection device and a power supply device capable of detecting a voltage value of an input voltage with high accuracy with a simple configuration. ..

In order to solve the above problem, one aspect of the present invention is a transformer having a primary side coil and a secondary side coil, and a plurality of switches connected between the first power supply line and the second power supply line. A switching circuit having an element and connected to the primary coil of the transformer, a rectifying unit that rectifies an AC signal output from the secondary coil of the transformer, and a power supply that controls switching of the switching circuit. A voltage detection device that detects the input voltage of a power supply device including a control unit, the voltage detection unit that detects the voltage output from one end of the secondary coil of the transformer as an input voltage, and the switching circuit. Among the plurality of switch elements, the voltage is at the timing of the midpoint of the period during which the switch element that conducts the primary coil between the first power supply line and the second power supply line is turned on. The voltage detection device includes a detection control unit that adjusts the detection timing of the voltage detection unit so that the detection unit detects the input voltage.

Further, one aspect of the present invention is that in the voltage detection device, the detection control unit is within a predetermined range that is not affected by the switching of the plurality of switch elements during the period in which the switch elements are turned on. It is characterized in that the detection timing is adjusted so as to be within the above-mentioned detection timing.

Further, one aspect of the present invention includes a smoothing circuit for smoothing the voltage output from one end of the secondary coil of the transformer in the voltage detection device, and the voltage detection unit is the smoothing. It is characterized in that the voltage smoothed by the circuit is detected as the input voltage.

Further, one aspect of the present invention is that in the voltage detection device, the detection control unit is within a predetermined range that is not affected by the switching of the plurality of switch elements during the period in which the switch elements are turned on. It is characterized in that the detection timing is adjusted so as to be within the above-mentioned detection timing. The switching circuit is a full-bridge circuit having four switch elements, and the detection control unit is a first connected to the first power supply line of the four switch elements of the full-bridge circuit. The voltage detection unit detects the input voltage at the timing of the midpoint of the period during which both the switch element and the second switch element connected to the second power supply line are in the ON state. It is characterized in that the detection timing of the voltage detection unit is adjusted.

Further, one aspect of the present invention is that in the voltage detection device, the detection control unit is within a predetermined range that is not affected by the switching of the plurality of switch elements during the period in which the switch elements are turned on. It is characterized in that the detection timing is adjusted so as to be within the above-mentioned detection timing. The power supply control unit controls the phase shift of the four switch elements, and the detection control unit changes the detection timing according to a change in the period during which both of them are in the ON state due to the phase shift control. It is a feature.

Further, one aspect of the present invention includes a non-volatile storage unit that stores the adjustment value of the detection timing as delay time information from a predetermined reference timing in switching of the plurality of switch elements in the voltage detection device. The detection control unit is characterized in that the detection timing is adjusted based on the delay time information stored in the non-volatile storage unit.

Further, one aspect of the present invention is a power supply device including the voltage detection device described above, the transformer, the switching circuit, the rectifier unit, and the power supply control unit.

According to the present invention, the voltage detection unit is at the timing of the midpoint of the period during which the switch element that conducts the primary coil between the first power supply line and the second power supply line is turned on. Adjusts the detection timing of the voltage detector so that As a result, the voltage detection device can detect an analog value of a stable input voltage while reducing the influence of the spike current at the time of switching. Therefore, the voltage detection device can detect the voltage value of the input voltage with high accuracy with a simple configuration.

It is a block diagram which shows an example of the power supply device by this embodiment. It is a figure which shows an example of the detection waveform of the smoothing circuit in this embodiment. It is a time chart which shows an example of the operation of the power supply device in this embodiment. It is a figure which shows an example of the feedback control of the power supply device in this embodiment.

Hereinafter, the voltage detection device and the power supply device according to the embodiment of the present invention will be described with reference to the drawings.

FIG. 1 is a block diagram showing an example of a power supply device 1 according to the present embodiment.
As shown in FIG. 1, the power supply device 1 includes a DC power supply 2, a choke coil 3, a smoothing capacitor 4, a voltage detection device 10, a switching circuit 20, a transformer 30, a rectifier unit 40, and a control unit 50. And.

The DC power supply 2 is, for example, a battery such as a lithium ion battery or a lead storage battery, and supplies DC power to the power supply device 1. The DC power supply 2 supplies DC power of a predetermined voltage between the power supply line L1 (first power supply line) and the power supply line L2 (second power supply line), for example.

The switching circuit 20 is, for example, a full bridge circuit having four switch elements (Q1 to Q4), and changes the direction of the current flowing through the load unit (transformer 30) by switching the plurality of switch elements (Q1 to Q4). .. The switching circuit 20 is connected to the primary coil 31 of the transformer 30, converts the DC power supplied from the DC power supply 2 into AC power, and supplies the DC power to the primary coil 31 of the transformer 30, which will be described later.
Further, the switching circuit 20 includes a first switch element 21 and a second switch element 22.

Each of the four switch elements (Q1 to Q4) is, for example, an N-type MOSFET (Metal-Oxide-Semiconductor Field-Effect Transistor).
The switch element Q1 and the switch element Q2 are connected in series between the power supply line L1 and the power supply line L2 via an intermediate node N1.
Further, the switch element Q3 and the switch element Q4 are connected in series between the power supply line L1 and the power supply line L2 via an intermediate node N2.

In the switch element Q1, the drain terminal is connected to the power supply line L1, the source terminal is connected to the node N1, and the gate terminal is connected to the control signal line output from the control unit 50.
In the switch element Q2, the drain terminal is connected to the node N1, the source terminal is connected to the power supply line L2, and the gate terminal is connected to the control signal line output from the control unit 50.

In the switch element Q3, the drain terminal is connected to the power supply line L1, the source terminal is connected to the node N2, and the gate terminal is connected to the control signal line output from the control unit 50.
In the switch element Q4, the drain terminal is connected to the node N2, the source terminal is connected to the power supply line L2, and the gate terminal is connected to the control signal line output from the control unit 50.

Here, the switch element Q1 and the switch element Q3 are included in the first switch element 21 connected to the power supply line L1. Further, the switch element Q2 and the switch element Q4 are included in the second switch element 22 connected to the power supply line L2. The switching circuit 20 is connected to the primary coil 31 of the transformer 30 and supplies an AC signal to the primary coil 31.
Further, the four switch elements (Q1 to Q4) are phase-shift controlled by the control unit 50 described later.

The transformer 30 has a primary coil 31 and a secondary coil 32, converts AC power supplied to the primary coil 31 and outputs the AC power from the secondary coil 32.
The primary coil 31 is connected between the node N1 and the node N2, and the AC signal generated by the switching circuit 20 is supplied.
The secondary coil 32 has a secondary coil 32A and a secondary coil 32B connected in series via a node N3 at an intermediate point (center tap).
The AC signal output from the secondary coil 32 of the transformer 30 is output to the rectifying unit 40.

The secondary coil 32A has a first end connected to a drain terminal of a switch element 41 of a rectifying unit 40 described later, and a second end connected to a node N3 (center tap).
Further, the secondary side coil 32B is connected to the node N3 (center tap) at the first end and to the drain terminal of the switch element 42 of the rectifying unit 40 described later at the second end.

The rectifier unit 40 is a synchronous rectifier circuit that rectifies an AC signal output from the secondary coil 32 of the transformer 30. The rectifying unit 40 includes a switch element 41 and a switch element 42 whose conduction state is controlled by a control unit 50 described later.

In the switch element 41, the drain terminal is connected to the first end (node N4) of the secondary coil 32A, the source terminal is connected to the ground terminal, and the gate terminal is connected to the control signal line output from the control unit 50. ..

In the switch element 42, the drain terminal is connected to the second end (node N5) of the secondary coil 32B, the source terminal is connected to the ground terminal, and the gate terminal is connected to the control signal line output from the control unit 50. ..
The switch element 41 and the switch element 42 are alternately turned on (conducting state) according to the direction of the current flowing through the primary coil 31 and the secondary coil 32 by the control signal output from the control unit 50. NS.

The choke coil 3 is connected between the node N3 and the node N7 to block a current higher than a target frequency and smooth the output voltage of the node N7.
The smoothing capacitor 4 is connected between the node N7 (output terminal) and the ground terminal to smooth the output voltage of the node N7.
The choke coil 3 and the smoothing capacitor 4 are used to remove noise from the output voltage and smooth it.

The voltage detection device 10 is a detection device that detects the input voltage of the power supply device 1, and includes a smoothing circuit 11, an ADC (Analog to Digital Converter) 12, an EEPROM (Electrically Erasable Programmable Read-Only Memory) 13, and an EEPROM (Electrically Erasable Programmable Read-Only Memory) 13. It includes a detection control unit 52 of the control unit 50.

The smoothing circuit 11 smoothes the voltage output from one end (for example, node N4) of the secondary coil 32 of the transformer 30. The smoothing circuit 11 smoothes the voltage of the secondary coil 32 in a state where the switch element 42 is turned on, and outputs the voltage to the ADC 12. The voltage output by the smoothing circuit 11 from the node N4 is a voltage obtained by outputting the input voltage of the power supply device 1 output from the DC power supply 2 via the transformer 30, and corresponds to the input voltage of the power supply device 1. It is a voltage. Therefore, it is possible to detect the input voltage of the power supply device 1 by detecting the voltage output by the smoothing circuit 11.
Further, the smoothing circuit 11 includes resistors (111, 112) and a capacitor 113.

The resistor 111 and the resistor 112 are connected in series between the node N4 and the ground terminal via an intermediate node N6. The resistor 111 and the resistor 112 divide the voltage output to the node N4 by the resistance voltage division and output the voltage from the node N6.
The capacitor 113 is connected between the node N6 and the ground terminal to smooth the voltage of the node N6.

The ADC 12 (an example of the voltage detection unit) detects the voltage smoothed by the smoothing circuit 11 as an input voltage. The ADC 12 controls the timing at which the smoothing circuit 11 detects the smoothed voltage based on the control of the detection control unit 52 described later, and uses the detected voltage value as the output voltage of the DC power supply 2 (power supply device 1). Detected as input voltage). The ADC 12 outputs the detected value to the control unit 50.

The EEPROM 13 (an example of the non-volatile storage unit) stores the adjustment value of the detection timing of the detection control unit 52, which will be described later, as delay time information from a predetermined reference timing in switching of a plurality of switch elements (Q1 to Q4). The EEPROM 13 stores the delay time information by, for example, calibration at the time of shipping inspection of the power supply device 1.

In addition, the EEPROM 13 stores various information used for controlling the power supply control unit 51, which will be described later. The EEPROM 13 stores, for example, the feedback control of the power supply control unit 51, the gain information used for the feedforward control, and the like in advance.

The control unit 50 is, for example, a processor including a CPU (Central Processing Unit) and the like, and controls the power supply device 1 in an integrated manner. The control unit 50 includes a power supply control unit 51 and a detection control unit 52.

The detection control unit 52 controls to detect the input voltage. The detection control unit 52 is a switch element (for example, the switch element Q1 and the switch element) that conducts the transformer 30 between the power supply line L1 and the power supply line L2 among the plurality of switch elements (Q1 to Q4) of the switching circuit 20. The detection timing of the ADC 12 is adjusted so that the ADC 12 detects the voltage at the timing of the midpoint of the period in which Q4) is turned on.

The detection control unit 52 adjusts the detection timing so that the detection timing falls within a predetermined range that is not affected by the plurality of switch elements (Q1 to Q4) during the period in which the switch element that conducts the transformer 30 described above is in the ON state. do. Specifically, the detection control unit 52 includes the first switch element 21 connected to the power supply line L1 and the power supply line L2 among the four switch elements (Q1 to Q4) of the full bridge circuit (switching circuit 20). The detection timing of the ADC 12 is adjusted so that the ADC 12 detects the voltage at the timing of the midpoint of the period during which both the second switch element 22 connected to the device and the second switch element 22 are turned on. The detection control unit 52 adjusts the detection timing of the ADC 12 so that the ADC 12 detects the voltage at the timing of the midpoint of the period during which both the switch element Q1 and the switch element Q4 are turned on, for example.

In the EEPROM 13, for example, delay time information based on the timing at which the switch element Q1 is turned off (non-conducting state) is stored in advance. The detection control unit 52 adjusts the detection timing based on the delay time information stored in the EEPROM 13 (nonvolatile storage unit). Further, the detection control unit 52 changes the detection timing according to the change in the period during which both are turned on by the phase shift control. Details of the adjustment of the detection timing will be described later.

The power supply control unit 51 controls the switching of the switching circuit 20 based on the input voltage detected by the voltage detection device 10 (detection control unit 52). The power supply control unit 51 controls switching of the four switch elements (Q1 to Q4) by, for example, phase shift control. The power supply control unit 51 performs feedback control based on the output current detected by a CT (Current Transformer) (not shown) and the output voltage detected by, for example, an ADC (not shown) of the node N7. , Feedback control is performed based on the input voltage detected by the voltage detection device 10 (detection control unit 52).

The power supply control unit 51 controls switching of four switch elements (Q1 to Q4) by phase shift control based on the amount of change in phase difference (Δ phase difference) obtained by feedback control and feedforward control. ..
The details of the feedback control and the feedforward control by the power supply control unit 51 will be described later.

Next, the operation of the voltage detection device 10 and the power supply device 1 according to the present embodiment will be described with reference to the drawings.
FIG. 2 is a diagram showing an example of the detection waveform of the smoothing circuit 11 in the present embodiment.

In FIG. 2, the waveform W0 is the waveform of the detection signal of the node N6 shown in FIG. 1 described above. The horizontal axis of the graph indicates time, and the vertical axis indicates the voltage of the detection signal.
As shown in FIG. 2, the waveform W0 is obtained when, for example, both the switch element Q1 and the switch element Q4 are in the on state, the switch element 42 of the rectifying unit 40 is in the on state, and the switch element 41 is in the off state. , The voltage of the detection signal rises.

In the waveform W0, the portion P1 where the voltage of the detection signal changes sharply corresponds to the vicinity of the switching timing of the switch elements (Q1 to Q4). Therefore, the ADC 12 avoids the detection at such a location P1 and detects the voltage at a timing such as time T1. That is, the detection control unit 52 adjusts so that the detection timing is within a predetermined range that is not affected by the plurality of switch elements (Q1 to Q4).

Next, the overall operation of the voltage detection device 10 and the power supply device 1 will be described with reference to FIG.
FIG. 3 is a time chart showing an example of the operation of the power supply device 1 in the present embodiment.

In FIG. 3, the waveforms W1 to W4 show the switching states of the switch elements Q1 to the switch element Q4 in order from the top. Further, the waveform W5 is a timing signal indicating a timing in which both the switch element Q1 and the switch element Q4 are in the ON state, and both the switch element Q2 and the switch element Q3 are in the ON state. In the waveform W5, both the switch element Q1 and the switch element Q4 represent the on state as the positive electrode property, and both the switch element Q2 and the switch element Q3 represent the on state as the negative electrode property.

Further, the waveform W6 is a detection signal output from the smoothing circuit 11 described above, and indicates a signal indicating a voltage corresponding to the input voltage. Further, the waveform W7 indicates a periodic interrupt of feedback (F / B) control by the power supply control unit 51.
Further, the waveform W8 indicates the conversion timing of the ADC 12.
The horizontal axis of the waveforms W1 to W8 shown in FIG. 3 is time.

In FIG. 3, the power supply control unit 51 of the control unit 50 controls the switching of the switch elements Q1 to the switch element Q4 by phase shift control as the period TR1 of one cycle of control, as shown in the waveforms W1 to W4. .. The power supply control unit 51 executes feedforward control and feedback control based on the input voltage detected by the voltage detection device 10 (detection control unit 52), calculates the phase difference, and performs phase shift control. The phase difference period TΔθ is, for example, a period from when the switch element Q3 is turned off to when the switch element Q1 is turned off.

Further, the detection control unit 52 detects the ADC 12 at the timing of the central portion of the T14ON (black-filled portion of the waveform W8) during the period when both the switch element Q1 and the switch element Q4 in the waveform W5 are in the ON state. Control. The detection control unit 52 acquires the voltage value detected by the ADC 12 as the corresponding input voltage, and outputs the input voltage to the power supply control unit 51.

The power supply control unit 51 calculates and updates the phase difference period TΔθ based on the input voltage detected by the voltage detection device 10 (detection control unit 52) (see waveform W7), and updates the phase difference period. The switching of the four switch elements (Q1 to Q4) of the switching circuit 20 is controlled based on TΔθ.

In FIG. 3, the enlarged waveform G1 shows the waveforms W1 to W6 and the waveform W8 in which the region A1 is enlarged. Here, the delay value DT34 is a delay value from the time when the switch element Q3, which is the starting point of the phase difference period TΔθ, is turned off to the time when the switch element Q4 is turned on. Further, the period T14ON is a period in which both the switch element Q1 and the switch element Q4 are in the ON state, as described above. The delay value DTCK is a delay value from the time when the switch element Q3 is turned off to the detection timing of the ADC 12.
In such a situation, the delay value DTCK is expressed by the following equation (1).

Delay value DTCK = Delay value DT34 + (Period of phase difference TΔθ-Delay value DT34) / 2
= Delay value DT34 + Period T14ON / 2 ... (1)

The delay value DTCK calculated based on the equation (1) is stored in the EEPROM 13.
Further, in the present embodiment, since the power supply control unit 51 performs phase shift control, the phase difference period TΔθ is changed according to the output current. Therefore, for example, the value of the phase difference period TΔθ and the delay value DTCK are stored in advance in the EEPROM 13 in association with each other.

For example, the detection control unit 52 acquires the delay value DTCK associated with the value of the phase difference period TΔθ from the EEPROM 13, and adjusts the detection timing of the ADC 12 by the acquired delay value DTCK. The detection period of the ADC 12 (see the black filling period of the waveform W8) includes the sample hold period of the ADC 12 and the analog-to-digital conversion period.
The detection control unit 52 outputs the detection value detected by the ADC 12 to the power supply control unit 51 as an output current according to the adjusted detection timing.

Next, the feedback control by the power supply control unit 51 will be described with reference to FIG.
FIG. 4 is a diagram showing an example of feedback control of the power supply device 1 in the present embodiment.

As shown in FIG. 4, the power supply control unit 51 executes feedback control based on the voltage deviation of the output voltage, the current deviation of the output current, and the power deviation of the output power, and the control amount of the feedback control (FB control amount). ) Is calculated.

Here, the voltage deviation of the output voltage is the difference between the target output voltage and the detected output voltage, and the current deviation of the output current is the difference between the target output current and the detected output current. The power deviation of the output power is the difference between the target output power and the detected output power. The output power is calculated by the power supply control unit 51 from the detected output current and output voltage.

Further, the power supply control unit 51 executes feedforward control based on the input voltage detected by the voltage detection device 10 (detection control unit 52), and combines feedback control and feedforward control to change the phase difference. Calculate the quantity (Δ phase difference). The power supply control unit 51 updates the phase difference of the phase shift control based on the amount of change in the phase difference (Δ phase difference). In this way, the power supply control unit 51 combines the feedback control and the feedforward control to perform phase shift control of the four switch elements (Q1 to Q4). The power supply device 1 according to the present embodiment can easily improve the response performance by performing feedforward control using the information of the input voltage.

Next, the calibration process (calibration process) related to the voltage detection of the power supply device 1 and the voltage detection device 10 according to the present embodiment will be described. The power supply device 1 and the voltage detection device 10 are subjected to the following calibration processing before shipment.

The control unit 50 of the power supply device 1 sets the input voltage from the DC power supply 2 of the power supply device 1 to, for example, the maximum value (Max value), the standard value (“Type value”, and the minimum value (Min value)) of the input voltage. By changing this, the delay value DTCK of the detection timing is adjusted so that the difference between the detected voltage value and the input voltage from the DC power supply 2 is equal to or less than a predetermined value. The control unit 50 performs the calibration process in this way. The delay value DTCK as a result of this is stored in the EEPROM.

As described above, the voltage detection device 10 according to the present embodiment is a voltage detection device 10 that detects an input voltage of a power supply device 1 including a transformer 30, a switching circuit 20, a rectifier unit 40, and a power supply control unit 51. It is provided with an ADC 12 (voltage detection unit) and a detection control unit 52. Here, the transformer 30 has a primary coil 31 and a secondary coil 32. The switching circuit 20 has a plurality of switch elements (Q1 to Q4) connected between the power supply line L1 (first power supply line) and the power supply line L2 (second power supply line), and is the primary of the transformer 30. It is connected to the side coil 31. The rectifying unit 40 rectifies the AC signal output from the secondary coil 32 of the transformer 30. The power supply control unit 51 controls the switching of the switching circuit 20. Further, the ADC 12 detects a voltage output from one end of the secondary coil 32 of the transformer 30 as an input voltage. The detection control unit 52 is a switch element (for example, the switch element Q1 and the switch element Q1) that conducts the primary coil 31 between the power supply line L1 and the power supply line L2 among the plurality of switch elements (Q1 to Q4) of the switching circuit 20. The detection timing of the ADC 12 is adjusted so that the ADC 12 detects the input voltage at the timing of the midpoint of the period during which the switch element Q4) is turned on.

As a result, the detection control unit 52 is at the midpoint of the period during which the switch element (for example, the switch element Q1 and the switch element Q4) that conducts the primary coil 31 between the power supply line L1 and the power supply line L2 is turned on. At the timing, the detection timing of the voltage detection unit is adjusted so that the ADC 12 detects the input voltage. That is, the voltage detection device 10 according to the present embodiment can detect an analog value of a stable input voltage while reducing the influence of the spike current at the time of switching. Therefore, the voltage detection device 10 according to the present embodiment can detect the voltage value of the input voltage with high accuracy with a simple configuration.

Further, in the present embodiment, the detection control unit 52 has a predetermined range that is not affected by a plurality of switch elements (Q1 to Q4) within the period (period T14ON) in which the switch elements (Q1 and Q2) are turned on. Adjust so that the detection timing fits within.
As a result, the voltage detection device 10 according to the present embodiment can reduce the influence of switching of the plurality of switch elements (Q1 to Q4), and thus can further improve the detection accuracy of the input voltage.

Further, the voltage detection device 10 according to the present embodiment includes a smoothing circuit 11 that smoothes the voltage output from one end of the secondary coil 32 of the transformer 30. The detection control unit 52 detects the voltage smoothed by the smoothing circuit 11 as an input voltage.
As a result, the voltage detection device 10 according to the present embodiment can detect the input voltage more stably, so that the detection accuracy of the input voltage can be further improved.

Further, in the present embodiment, the switching circuit 20 is a full bridge circuit having four switch elements (Q1 to Q4). The detection control unit 52 includes a first switch element 21 connected to the power supply line L1 and a second switch element connected to the power supply line L2 among the four switch elements (Q1 to Q4) of the full bridge circuit. The detection timing of the ADC 12 is adjusted so that the ADC 12 detects the input voltage at the timing of the midpoint of the period in which both the devices and 22 are turned on.

As a result, the voltage detection device 10 according to the present embodiment detects the voltage in the ADC 12 at the timing of the midpoint of the period during which both the first switch element 21 and the second switch element 22 are in the ON state. Therefore, even when the switching circuit 20 is a full bridge circuit, the input voltage can be detected appropriately.

Further, in the present embodiment, the power supply control unit 51 controls the phase shift of the four switch elements (Q1 to Q4). The detection control unit 52 changes the detection timing according to the change in the period during which both are turned on by the phase shift control.

As a result, the voltage detection device 10 according to the present embodiment can appropriately adjust the detection timing of the ADC 12 according to the change in the period during which both are turned on by the phase shift control. Therefore, the voltage detection device 10 according to the present embodiment can appropriately detect the input voltage even when the phase shift control is performed.

Further, the voltage detection device 10 according to the present embodiment stores the adjustment value of the detection timing as the delay time information from the predetermined reference timing in the switching of the plurality of switch elements (Q1 to Q4) in the EEPROM 13 (nonvolatile storage unit). To be equipped. The detection control unit 52 adjusts the detection timing based on the delay time information stored in the EEPROM 13.
As a result, the voltage detection device 10 according to the present embodiment can appropriately detect the output current by a simple configuration including the EEPROM 13 (nonvolatile storage unit).

Further, the power supply device 1 according to the present embodiment includes the voltage detection device 10 described above, a transformer 30, a switching circuit 20, a rectifier unit 40, and a power supply control unit 51.
As a result, the power supply device 1 according to the present embodiment has the same effect as the voltage detection device 10 described above, and can improve the detection accuracy of the input voltage. Further, since the power supply device 1 according to the present embodiment can improve the detection accuracy of the input voltage, for example, feedforward control can be easily executed.

The present invention is not limited to the above embodiment, and can be modified without departing from the spirit of the present invention.
For example, in the above embodiment, an example in which the ADC 12 is used as an example of the voltage detection unit has been described, but the present invention is not limited to this, and a voltage detection unit of another type may be used. For example, instead of the ADC 12, a comparator that compares with a predetermined threshold voltage depending on the detection timing may be used.

Further, in the above embodiment, the power supply device 1 has described an example in which a synchronous rectifier circuit is used as the rectifier unit 40, but the present invention is not limited to this, and for example, the rectifier unit 40 is asynchronous with a diode. A rectifier circuit may be used.

Further, in the above embodiment, the example in which the voltage detection device 10 detects the input voltage of the power supply device 1 has been described, but the present invention is not limited to this, and for example, the input of another device such as a motor control device is input. The voltage may be detected.

Further, in the above embodiment, an example in which a center tap type transformer is used as an example of the transformer 30 has been described, but the present invention is not limited to this, and other types of transformers may be used.

Further, in the above embodiment, an example in which the control unit 50 includes both a power supply control unit 51 that controls as a power supply circuit and a detection control unit 52 that controls voltage detection has been described, but the present invention is limited to this. For example, one of the power supply control unit 51 and the detection control unit 52 may be provided outside the control unit 50.

Further, in the above embodiment, the detection control unit 52 causes the ADC 12 to detect the voltage at the timing of the midpoint of the period during which both the first switch element 21 and the second switch element 22 are in the ON state. Although an example of adjusting the detection timing has been described in the above, the present invention is not limited to this. For example, the detection control unit 52 may adjust to a detection timing deviated from the timing of the intermediate point as long as it is within a predetermined range that is not affected by the plurality of switch elements (Q1 to Q4).

Further, in the above embodiment, the example in which the voltage detection device 10 is provided with the smoothing circuit 11 has been described, but the present invention is not limited to this, and the voltage detection device 10 may be in another form not provided with the smoothing circuit 11. .. Further, the smoothing circuit 11 is not limited to the one described in the above embodiment, and may be a smoothing circuit of another type.

For example, the smoothing circuit 11 may preferentially include resistors (111, 112) and may not include a capacitor 113.
Further, in the smoothing circuit 11 described above, the capacitor 113 may be added within a range that does not affect the detection when, for example, noise or voltage vibration is a concern.

Further, in the above embodiment, the example in which the switching circuit 20 is a full bridge circuit has been described, but the present invention is not limited to this, and for example, a half bridge circuit or another type of switching circuit may be used.
Further, in the above embodiment, the power supply device 1 has been described as a power supply circuit using a full bridge circuit and a transformer 30, but the present invention is not limited to this, and the power supply device 1 may be applied to a power supply circuit of another type. .. For example, the power supply circuit is not limited to the insulated type / non-insulated type, and may be another type.

1 Power supply 2 DC power supply 3 Choke coil 4 Smoothing capacitor 10 Voltage detector 11 Smoothing circuit 12 ADC
13 EEPROM
20 Switching circuit 21 First switch element 22 Second switch element 30 Transformer 31 Primary side coil 32, 32A, 32B Secondary side coil 40 Rectifier unit 41, 42, Q1, Q2, Q3, Q4 Switch element 50 Control unit 51 Power supply control unit 52 Detection control unit 111, 112 Resistance 113 Capacitor

Claims (7)

It has a transformer having a primary coil and a secondary coil, and a plurality of switch elements connected between a first power supply line and a second power supply line, and is connected to the primary coil of the transformer. Voltage detection that detects the input voltage of a power supply device including a switching circuit, a rectifying unit that rectifies an AC signal output from the secondary coil of the transformer, and a power supply control unit that controls switching of the switching circuit. It ’s a device,
A voltage detection unit that detects the voltage output from one end of the secondary coil of the transformer as an input voltage, and
Of the plurality of switch elements of the switching circuit, the timing of the midpoint of the period during which the switch element that conducts the primary coil between the first power supply line and the second power supply line is turned on. A voltage detection device comprising a detection control unit that adjusts the detection timing of the voltage detection unit so that the voltage detection unit detects the input voltage. The claim is characterized in that the detection control unit adjusts the detection timing within a predetermined range that is not affected by the switching of the plurality of switch elements during the period in which the switch elements are turned on. Item 1. The voltage detection device according to item 1. A smoothing circuit for smoothing the voltage output from one end of the secondary coil of the transformer is provided.
The voltage detection device according to claim 1 or 2, wherein the voltage detection unit detects a voltage smoothed by the smoothing circuit as the input voltage. The switching circuit is a full bridge circuit having four switch elements.
The detection control unit includes a first switch element connected to the first power supply line and a second switch element connected to the second power supply line among the four switch elements of the full bridge circuit. The first aspect of the present invention is that the detection timing of the voltage detection unit is adjusted so that the voltage detection unit detects the input voltage at the timing of the midpoint of the period in which both the switch element and the switch element are on. The voltage detection device according to any one of claims 3. The power supply control unit controls the phase shift of the four switch elements.
The voltage detection device according to claim 4, wherein the detection control unit changes the detection timing according to a change in the period during which both of them are turned on by the phase shift control. A non-volatile storage unit that stores the adjustment value of the detection timing as delay time information from a predetermined reference timing in switching of the plurality of switch elements is provided.
The voltage detection according to any one of claims 1 to 5, wherein the detection control unit adjusts the detection timing based on the delay time information stored in the non-volatile storage unit. Device. A power supply device including the voltage detection device according to any one of claims 1 to 6, the transformer, the switching circuit, the rectifier unit, and the power supply control unit.

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