JP7275764B2 - Correction circuit and power supply - Google Patents

Description

The present invention relates to a correction circuit and a power supply device.

Research and development of technology related to switching power supply devices that supply DC voltage are being conducted.

A switching power supply device may cause intermittent oscillation when the consumption voltage of a connected load is small. Since intermittent oscillation may destabilize the DC voltage supplied by the switching power supply, it is desirable to suppress it.

In relation to this, there is known a switching power supply device that uses a dummy resistor to prevent intermittent oscillation (see Patent Document 1).

JP-A-08-340675

Here, a main converter that steps up or steps down a DC voltage supplied from a DC power source that supplies DC voltage, a sub converter that steps down or steps up a DC voltage supplied from the DC power source, and a voltage output from the main converter Switching power supplies are also known that include a controller that controls the magnitude of . The main converter is connected to a load such as a battery mounted on an electric vehicle, and supplies DC voltage to the load. On the other hand, the sub-converter generates a drive circuit for driving the main converter and a drive voltage for the controller. The sub-converter outputs the generated drive voltage to the drive circuit and outputs the drive voltage to the control unit. The drive circuit operates based on the drive voltage supplied from the sub-converter to drive the main converter.

Also, in such a switching power supply device, the control section monitors the voltage of the auxiliary winding provided on the secondary side of the transformer of the sub-converter. Based on the monitored voltage, the controller estimates the magnitude of the DC voltage output from the DC power supply.

However, in such a switching power supply device, intermittent oscillation occurs in the main converter when the load connected to the main converter becomes lighter than a certain level. If the load on the main converter becomes light enough to cause intermittent oscillation, the load on the drive circuit that drives the main converter will lighten, and the load on the sub-converter that supplies the drive voltage to the drive circuit will also lighten. , the oscillation waveform of the sub-converter begins to significantly differ from the oscillation waveform of the sub-converter when the main converter is fully oscillating. In other words, even if the main converter outputs a constant voltage, the voltage monitored by the control unit is when the main converter is fully oscillating, or when the main converter is intermittently oscillating. means different in As a result, the control unit may not be able to accurately estimate the magnitude of the DC voltage output from the DC power supply when intermittent oscillation occurs in the main converter.

SUMMARY OF THE INVENTION The present invention has been made in consideration of such circumstances, and is a correction circuit capable of improving the accuracy of control performed based on the second voltage even when intermittent oscillation occurs in the main converter. , and a power supply device.

One aspect of the present invention includes a main converter that converts an input voltage and supplies power to a load, and a sub-converter that supplies power to one or more other circuits including a drive circuit that drives the main converter. A correction circuit for correcting the second voltage generated by the sub-converter based on the first voltage generated by the main converter.

According to the present invention, even when intermittent oscillation occurs in the main converter, it is possible to improve the accuracy of control performed based on the second voltage.

It is a figure which shows an example of a structure of the power supply device 1 which concerns on embodiment. FIG. 10 is a diagram showing an example of temporal change in the magnitude of the third voltage supplied from the duty detection circuit 14 to the control unit 16 when intermittent oscillation occurs in the main converter 11; FIG. 10 is a diagram showing an example of temporal change in the magnitude of the third voltage supplied from the duty detection circuit 14 to the control unit 16 when the main converter 11 is fully oscillated; It is a figure which shows an example of 1st correspondence information. It is a figure which shows an example of 2nd correspondence information. It is a figure which shows an example of a structure of the power supply device 1 which concerns on the modification 1 of embodiment. It is a figure which shows an example of a structure of the power supply device 1 which concerns on the modification 2 of embodiment.

<Embodiment>
BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, embodiments of the present invention will be described with reference to the drawings. In this specification, a conductor for transmitting an electrical signal corresponding to DC power or an electrical signal corresponding to AC power is referred to as a transmission path. A transmission line is, for example, a conductor printed on a substrate. Note that the transmission line may be a conducting wire or the like, which is a linear conductor, instead of the conductor. Further, in this specification, the term "voltage" means a potential difference from a predetermined reference potential, and illustration and description of the reference potential are omitted. Here, the reference potential may be any potential. In the following, as an example, a case where the reference potential is the ground potential will be described.

<Configuration of power supply>
A configuration of the power supply device 1 according to the embodiment will be described. FIG. 1 is a diagram showing an example of the configuration of a power supply device 1 according to an embodiment. Each circuit and each device shown in FIG. 1 operates under a common ground potential. Therefore, in FIG. 1, the transmission line connected to the ground (that is, the ground line, etc.) is omitted.

Power supply device 1 is connected to DC power supply 10 . The DC power supply 10 may be any power supply that outputs a DC voltage. The DC power supply 10 is, for example, a DC power supply that rectifies and smoothes an AC voltage supplied from a commercial power supply, a secondary battery, a switching power supply, or the like. A switching power supply is, for example, a switching converter or the like. For convenience of explanation, the DC voltage output from the DC power supply 10 to the power supply device 1 will be referred to as an input voltage below. Note that the power supply device 1 may be configured to be connected to an AC power supply capable of outputting an AC voltage instead of being connected to the DC power supply 10 . In this case, the power supply device 1 includes an AC (Alternating Current)/DC (Direct Current) converter that converts the supplied AC voltage into a DC voltage.

Also, the power supply device 1 can be connected to a load (not shown). An input voltage is supplied to the load from the power supply device 1 . The load is, for example, a rechargeable secondary battery (eg, lithium ion battery, lithium polymer battery, etc.) or the like. Note that the load may be another device that operates according to a DC voltage instead of the secondary battery. Further, the secondary battery may be, for example, a battery mounted on an electric vehicle, or may be another secondary battery.

The power supply device 1 also includes a main converter 11 , a sub-converter 12 , a drive circuit 13 , a duty detection circuit 14 and a control section 16 .

The main converter 11 is a DC/DC converter. The main converter 11 steps down or steps up the input voltage supplied from the DC power supply 10 . Also, the main converter 11 is driven by a drive circuit 13, which will be described later, to step-down or step-up the input voltage. The main converter 11 outputs the voltage obtained by stepping down or stepping up the input voltage to the aforementioned load and the duty detection circuit 14 as the first voltage. The first voltage is, more specifically, a voltage output from the secondary side of a transformer (not shown) included in the main converter 11 . Therefore, the first voltage before being smoothed is a high-frequency pulse voltage oscillating at the drive frequency of the drive circuit 13, which will be described later. Here, when outputting the first voltage to the load, the main converter 11 may or may not smooth the first voltage. However, if the main converter 11 does not smooth the first voltage when outputting the first voltage to the load, the load may be provided with a circuit for smoothing the first voltage. A circuit for smoothing the first voltage may be connected between. Further, when outputting the first voltage to the duty detection circuit 14, the main converter 11 outputs the first voltage to the duty detection circuit 14 without smoothing it. When the power supply device 1 is connected to an AC power supply, the main converter 11 takes the DC voltage supplied from the AC/DC converter as an input voltage and steps up or down the input voltage.

Sub-converter 12 is a DC/DC converter. The sub-converter 12 steps down or steps up the input voltage supplied from the DC power supply 10 . The sub-converter 12 also includes a plurality of switching elements (not shown) and a drive circuit that drives each of the plurality of switching elements. That is, the sub-converter 12 is driven by the drive circuit. Here, in the embodiment, description of each of the plurality of switching elements and the drive circuit is omitted.

Sub-converter 12 generates a drive voltage based on the input voltage supplied from DC power supply 10 . The drive voltage is, more specifically, a voltage output from the secondary side of a transformer (not shown) included in the sub-converter 12 . Therefore, the drive voltage before smoothing is a high-frequency pulse voltage oscillating at the drive frequency of a drive circuit (not shown) that drives the sub-converter 12 . Sub-converter 12 outputs the generated drive voltage to drive circuit 13 . At this time, the sub-converter 12 may be configured to smooth the drive voltage or may be configured not to smooth the drive voltage. However, if the drive voltage is not smoothed when the sub-converter 12 outputs the drive voltage to the drive circuit 13, the drive circuit 13 may include a circuit for smoothing the drive voltage. A configuration in which a circuit for smoothing the driving voltage is connected between the circuit 13 may be employed. Hereinafter, for convenience of explanation, the drive voltage output to the drive circuit 13 will be referred to as a first drive voltage.

The sub-converter 12 also outputs the generated drive voltage to the control section 16 . At this time, the sub-converter 12 may be configured to smooth the drive voltage or may be configured not to smooth the drive voltage. As an example, the case where the sub-converter 12 smoothes the drive voltage when the sub-converter 12 outputs the drive voltage to the control unit 16 will be described below. However, if the sub-converter 12 does not smooth the drive voltage when the sub-converter 12 outputs the drive voltage to the control unit 16, the control unit 16 may be configured to include a circuit for smoothing the drive voltage. A configuration in which a circuit for smoothing the driving voltage is connected between the converter 12 and the control unit 16 may be employed. It should be noted that an LDO (Low Drop Out) may be provided between the sub-converter 12 and the control unit 16, or an LDO may not be provided. Hereinafter, for convenience of explanation, the drive voltage output to the control section 16 will be referred to as a second drive voltage.

Sub-converter 12 also outputs the smoothed second drive voltage to duty detection circuit 14 as a reference voltage. The reference voltage is a voltage used in operations performed by the duty detection circuit 14, which will be described later. The operation of the duty detection circuit 14 using the reference voltage will be described later. However, if the sub-converter 12 does not smooth the reference voltage when outputting the second drive voltage to the duty detection circuit 14, the duty detection circuit 14 may include a circuit for smoothing the reference voltage. A circuit for smoothing the reference voltage may be connected between converter 12 and duty detection circuit 14 .

Further, the sub-converter 12 has an auxiliary winding on the secondary side of a transformer (not shown) included in the sub-converter 12 . The voltage of the auxiliary winding is smoothed by a smoothing circuit (not shown). Then, the smoothed voltage is detected as a second voltage by the voltage detection circuit 15, which will be described later. Note that the voltage is the voltage output from the auxiliary winding, as described above. Therefore, the second voltage before being smoothed is a high-frequency pulse voltage oscillating at the drive frequency of a drive circuit (not shown) that drives the sub-converter 12 . Moreover, the second voltage is, more specifically, a voltage whose crest value is proportional to the input voltage output from the DC power supply 10 .

Here, in the embodiment, the sub-converter 12 supplies voltage only to the circuits and the like (in the embodiment, the drive circuit 13, the duty detection circuit 14, and the control section 16) in the power supply device 1. The power may be supplied to an external circuit, device, or the like.

Drive circuit 13 operates with the first drive voltage supplied from sub-converter 12 . A drive circuit 13 drives the main converter 11 . For example, in response to switching control such as PWM (Pulse Width Modulation) control by the control unit 16, the drive circuit 13 causes the main converter 11 to output a voltage having a magnitude corresponding to the switching control as the first voltage. Below, the case where the said switching control is PWM control is demonstrated.

The duty detection circuit 14 outputs a voltage corresponding to the difference between the first voltage supplied from the main converter 11 and the reference voltage supplied from the sub-converter 12 to the control section 16 as the third voltage. In addition, as described above, the first voltage is a voltage before the first voltage is smoothed. The duty detection circuit 14 includes a filter 141 and a comparator 142, for example. Note that the duty detection circuit 14 may have any configuration as long as it includes the filter 141 and the comparator 142 . Therefore, FIG. 1 omits the configuration of the duty detection circuit 14 other than the filter 141 and the comparator 142 . Note that the duty detection circuit 14 may be configured such that the reference voltage is supplied from another circuit, device, or the like instead of the sub-converter 12 .

Filter 141 filters the first voltage supplied from main converter 11 . Thereby, the filter 141 removes noise from the first voltage. Filter 141 outputs the filtered first voltage to the inverting input terminal of comparator 142 .

The comparator 142 outputs a voltage corresponding to the difference between the first voltage supplied from the filter 141 to the inverting input terminal of the comparator 142 and the second voltage supplied from the sub-converter 12 to the non-inverting input terminal of the comparator 142 as a reference voltage. is output to the control unit 16 as the third voltage. The comparator 142 normally outputs an H level or L level voltage according to the magnitude relationship between the voltage supplied to the inverting input terminal and the reference voltage. However, in the power supply device 1, the first voltage supplied to the inverting input terminal is the voltage before the first voltage is smoothed. Therefore, the magnitude relationship between the first voltage and the reference voltage is reversed over time. In the power supply device 1 , the speed at which the magnitude relationship between the first voltage and the reference voltage is reversed is faster than the response speed of the comparator 142 . As a result, when the first voltage is supplied to the inverting input terminal, the comparator 142 outputs an intermediate voltage between the H level and the L level according to the first voltage supplied to the inverting input terminal and the reference voltage. is output to the control unit 16 as the third voltage. However, the comparator 142 outputs the H level or L level voltage as the third voltage when the first voltage whose magnitude changes so that the magnitude relationship is not reversed is supplied to the inverting input terminal. As an example, the case where the comparator 142 outputs an H-level voltage will be described below. The H level voltage is a voltage higher than 0 volts and may be any voltage as long as it can be distinguished from the intermediate voltage. Comparator 142 is an example of an oscillation state detection circuit. That is, in the power supply device 1, the comparator 142 outputs the voltage corresponding to the difference between the first voltage supplied from the filter 141 and the second voltage supplied from the sub-converter 12 to the control unit 16 as the third voltage. may be replaced with other circuits having the function of Also, the third voltage may be a voltage generated by another method as long as it is a voltage corresponding to the difference. Also, the magnitude of the third voltage in the present embodiment is merely an example, and may be another magnitude.

As described above, the voltage detection circuit 15 detects the voltage of the auxiliary winding on the secondary side of the transformer included in the sub-converter 12 as the second voltage. Here, the voltage of the auxiliary winding is the voltage after being smoothed as described above. The voltage detection circuit 15 outputs the detected second voltage to the control section 16 . The voltage detection circuit 15 may be configured to amplify the detected second voltage and then output it to the control section 16 . Here, the second voltage detected by the voltage detection circuit 15 is an example of the second voltage output from the sub-converter.

The control unit 16 operates with the second drive voltage supplied from the sub-converter 12 . Also, the control unit 16 can estimate the magnitude of the input voltage output from the DC power supply 10 based on the second voltage supplied from the voltage detection circuit 15 . Then, the control unit 16 can perform PWM control of the drive circuit 13 based on the estimated magnitude. Note that the control unit 16 may be configured such that the second drive voltage is supplied from another circuit, device, or the like instead of the sub-converter 12 .

Here, in the power supply device 1, intermittent oscillation occurs in the main converter 11 when the load connected to the main converter 11 becomes lighter than a certain amount. When the load becomes so light that intermittent oscillation occurs in the main converter 11, the oscillation waveform of the sub-converter 12 becomes significantly different from the oscillation waveform of the sub-converter 12 when the main converter 11 is in full oscillation. begin to appear. That is, even if the main converter 11 is outputting a constant voltage, the second voltage detected by the voltage detection circuit 15 may be This means that it is different when intermittent oscillation occurs.

Therefore, the control unit 16 includes a storage unit (not shown) that stores two types of correspondence information, first correspondence information and second correspondence information. The first correspondence information is correspondence information corresponding to the case where the main converter 11 is fully oscillated. The second correspondence information is correspondence information corresponding to the intermittent oscillation occurring in the main converter 11 . The correspondence information is information in which the input voltage and the second voltage are associated with each other. More specifically, the correspondence information includes the input voltage output from the DC power supply 10 and the second voltage output from the voltage detection circuit 15 to the control unit 16 when the input voltage is output from the DC power supply 10. is associated information (that is, information indicating the correlation between the input voltage and the second voltage). A predetermined voltage range of the third voltage output from the duty detection circuit 14 is associated with the first correspondence information as the first voltage range. A predetermined voltage range of the third voltage output from the duty detection circuit 14 is associated with the second correspondence information as a second voltage range.

The reason why the voltage range of the third voltage is associated with each of the first correspondence information and the second correspondence information is that in the power supply device 1, the magnitude of the third voltage output from the duty detection circuit 14 is This is because the case where the converter 11 is fully oscillated differs from the case where the main converter 11 is oscillated intermittently. For example, in the power supply device 1, the duty detection circuit 14 adjusts the design of the filter 141 included in the duty detection circuit 14, so that the first power supplied from the main converter 11 when intermittent oscillation occurs in the main converter 11. The voltage can be made less than the aforementioned reference voltage by the filter 141, and the first voltage supplied from the main converter 11 can be made greater than or equal to the reference voltage when the main converter 11 is fully oscillated.

Here, FIG. 2 is a diagram showing an example of temporal change in magnitude of the third voltage supplied from the duty detection circuit 14 to the control section 16 when intermittent oscillation occurs in the main converter 11 . The horizontal axis of the graph shown in FIG. 2 indicates elapsed time. The vertical axis of the graph shown in FIG. 2 indicates the magnitude of the voltage. A graph G11 shown in FIG. 2 shows temporal changes in the magnitude of the first voltage supplied from the main converter 11 to the duty detection circuit 14 in this case. A graph G12 shown in FIG. 2 shows temporal changes in the magnitude of the first voltage after being filtered by the filter 141 in this case. A graph G13 shown in FIG. 2 shows temporal changes in the magnitude of the third voltage output from the duty detection circuit 14 in this case. As shown in FIG. 2, in this case, the third voltage output from the duty detection circuit 14 is held at the H level (however, voltage fluctuations due to noise, errors, etc. may always occur). .

On the other hand, FIG. 3 is a diagram showing an example of temporal changes in the magnitude of the third voltage supplied from the duty detection circuit 14 to the control section 16 when the main converter 11 is fully oscillated. The horizontal axis of the graph shown in FIG. 3 indicates elapsed time. The vertical axis of the graph shown in FIG. 3 indicates the magnitude of the voltage. A graph G21 shown in FIG. 3 shows temporal changes in the magnitude of the first voltage supplied from the main converter 11 to the duty detection circuit 14 in this case. A graph G22 shown in FIG. 3 shows temporal changes in the magnitude of the first voltage after being filtered by the filter 141 in this case. A graph G23 shown in FIG. 3 shows temporal changes in the magnitude of the third voltage output from the duty detection circuit 14 in this case. As shown in FIG. 3, in this case, the third voltage output from the duty detection circuit 14 is held as an intermediate voltage between the H level voltage and the L level voltage (however, noise, error, etc. voltage fluctuations due to are always possible).

Thus, in the power supply device 1, the magnitude of the third voltage output from the duty detection circuit 14 varies depending on whether the main converter 11 is in full oscillation or intermittent oscillation is occurring in the main converter 11. different in Thereby, the control unit 16 causes the main converter 11 to perform full oscillation and intermittent oscillation based on the magnitude of the third voltage supplied from the duty detection circuit 14 (that is, the third voltage supplied from the comparator 142 described above). It is possible to determine which of

That is, based on the third voltage supplied from the duty detection circuit 14, the control unit 16 selectively reads either the first correspondence information or the second correspondence information from the storage unit. When the third voltage is included in the first voltage range, the control section 16 reads the first correspondence information from the storage section. The first voltage range is a voltage range whose lower limit is equal to or higher than the aforementioned reference voltage. On the other hand, when the third voltage is included in the second voltage range, the control section 16 reads the second correspondence information from the storage section. The second voltage range is a voltage range whose upper limit is less than the aforementioned reference voltage.

Here, FIG. 4 is a diagram showing an example of the first correspondence information. The table shown in FIG. 4 is a table in which the input voltage and the second voltage are associated with each other when the main converter 11 is in full oscillation. The control unit 16 reads, for example, the table shown in FIG. 4 from the storage unit as the first correspondence information. Note that the graph shown in FIG. 4 is a graph created based on the table. The horizontal axis of the graph indicates the second voltage. The vertical axis of the graph indicates the input voltage. That is, in this case, the control unit 16 outputs the input voltage associated with the second voltage from the DC power supply 10 based on the second voltage supplied from the voltage detection circuit 15 and the first correspondence information. input voltage.

On the other hand, FIG. 5 is a diagram showing an example of the second correspondence information. The table shown in FIG. 5 is a table in which the input voltage and the second voltage are associated with each other when intermittent oscillation occurs in the main converter 11 . The control unit 16 reads, for example, the table shown in FIG. 5 from the storage unit as the second correspondence information. Note that the graph shown in FIG. 5 is a graph created based on the table. The horizontal axis of the graph indicates the second voltage. The vertical axis of the graph indicates the input voltage. That is, in this case, the control unit 16 outputs the input voltage associated with the second voltage from the DC power supply 10 based on the second voltage supplied from the voltage detection circuit 15 and the second correspondence information. input voltage.

The selection of either the first correspondence information or the second correspondence information by the control unit 16 according to the third voltage supplied from the duty detection circuit 14 means that the second voltage supplied from the sub-converter 12 is controlled by the control unit 16 corresponds to correction. That is, the control section 16 corrects the second voltage supplied from the voltage detection circuit 15 based on the third voltage. In other words, control unit 16 corrects the second voltage output from sub-converter 12 based on the first voltage supplied to duty detection circuit 14 . Thereby, the power supply device 1 (or the correction circuit 20) can improve the accuracy of the control performed based on the second voltage even when the main converter 11 intermittently oscillates. For example, the control unit 16 can accurately estimate the magnitude of the input voltage output from the DC power supply 10 . As a result, the power supply device 1 can accurately control the first voltage output from the main converter 11 even when the main converter 11 intermittently oscillates.

Note that the storage unit described above may be an external storage device communicably connected to the control unit 16 .

<Modification 1 of Embodiment>
Modification 1 of the embodiment will be described below. In addition, in the modified example 1 of the embodiment, the same reference numerals are given to the same components as in the embodiment, and the description thereof is omitted. The power supply device 1 according to Modification 1 of the embodiment detects the second voltage output from the voltage detection circuit 15 based on the first voltage output from the main converter 11 without using the above-described second correspondence information. to correct.

FIG. 6 is a diagram showing an example of the configuration of the power supply device 1 according to Modification 1 of the embodiment. A power supply device 1 according to Modification 1 of the embodiment includes a switching element S1, a switching element S2, a resistor R1, and a resistor R2 in addition to the configuration shown in FIG. Note that the power supply device 1 may be configured to include other circuit elements, other circuits, and other devices as long as the functions of the power supply device 1 described below are not impaired.

The switching element S1 is a PNP transistor in the example shown in FIG. The switching element S1 may be an NPN transistor instead of a PNP transistor, or may be another switching element such as a field effect transistor. In the following, for convenience of explanation, the state in which current flows between the emitter and collector of the switching element S1 is referred to as the ON state of the switching element S1. For convenience of explanation, the state in which no current flows between the emitter and the collector of the switching element S1 will be referred to as the OFF state of the switching element S1.

The switching element S2 is an NPN transistor in the example shown in FIG. The switching element S2 may be a PNP transistor instead of an NPN transistor, or may be another switching element such as a field effect transistor. Hereinafter, for convenience of explanation, the state in which current flows between the emitter and collector of the switching element S2 is referred to as the ON state of the switching element S2. In the following, for convenience of explanation, the state in which no current flows between the emitter and collector of the switching element S2 is referred to as the OFF state of the switching element S2.

The emitter of the switching element S1 is connected via a transmission line to a transmission line for outputting the second drive voltage from the sub-converter 12 to the control section 16, among the transmission lines connecting the sub-converter 12 and the control section 16. be. In the following, for convenience of explanation, the transmission line will be referred to as a transmission line EL1 as shown in FIG. Also, the collector of the switching element S1 is connected to one end of the resistor R1 through the transmission line. The other end of the resistor R1 is grounded through the transmission line. Also, the base of the switching element S1 is connected to one end of the resistor R2 via a transmission line. The other end of the resistor R2 is connected via a transmission line to a transmission line that connects the emitter and the transmission line EL1. Also, the collector of the switching element S2 is connected via a transmission line to a transmission line that connects the base of the switching element S1 and the resistor R2. Also, the emitter of the switching element S2 is grounded through the transmission line. Also, the base of the switching element S2 is connected to the control unit 16 via a transmission line.

Note that in the power supply device 1 according to Modification 1 of the embodiment, the duty detection circuit 14, the control unit 16, the switching element S1, the switching element S2, the resistor R1, and the resistor R2 configure the correction circuit 20A. are doing.

Here, the control unit 16 according to Modification 1 of the embodiment determines whether full oscillation or intermittent oscillation occurs in the main converter 11 according to the third voltage supplied from the duty detection circuit 14. . Specifically, the control unit 16 determines that the main converter 11 is fully oscillated when the third voltage is at the H level. In this case, the controller 16 does not apply current to the base. Note that the control unit 16 may be configured to determine that the main converter 11 is fully oscillated when the third voltage is included in a voltage range equal to or higher than the H-level voltage. On the other hand, the control unit 16 determines that intermittent oscillation is occurring in the main converter 11 when the third voltage is a voltage intermediate between the H level and the L level. In this case, the controller 16 causes current to flow through the base. Note that the control unit 16 determines that the main converter 11 is fully oscillated when the voltage range includes the intermediate voltage and does not include the H-level voltage. good.

When no current flows through the base of switching element S2, the state of switching element S2 is the OFF state. In this case, no current flows from the transmission line EL1 to the base of the switching element S1. As a result, in this case, the state of the switching element S1 is turned off.

On the other hand, when current flows through the base of the switching element S2, the state of the switching element S2 is the ON state. In this case, a current flows from the transmission line EL1 to the base of the switching element S1. That is, in this case, the state of the switching element S1 is turned on. A current corresponding to the resistance value of the resistor R1 flows from the transmission line EL1 to the ground. As a result, the load on sub-converter 12 increases.

Utilizing this, in the power supply device 1 according to the first modification of the embodiment, the voltage is supplied from the voltage detection circuit 15 to the control unit 16 regardless of whether the main converter 11 undergoes full oscillation or intermittent oscillation. The correlation between the second voltage that is applied and the input voltage that is output from the DC power supply 10 can be matched with the correlation indicated by the above-described first correspondence information. This can be achieved by adjusting the resistance value of resistor R1. That is, the control section 16 corrects the second voltage supplied from the voltage detection circuit 15 based on the third voltage supplied from the duty detection circuit 14 . In other words, the control section 16 corrects the second voltage based on the first voltage supplied to the duty detection circuit 14 . As a result, even when intermittent oscillation occurs in the main converter 11, the power supply device 1 (or the correction circuit 20A) according to Modification 1 of the embodiment can improve the accuracy of the control performed based on the second voltage. can be improved. For example, the control unit 16 can accurately estimate the magnitude of the input voltage output from the DC power supply 10 . As a result, the power supply device 1 can accurately control the first voltage output from the main converter 11 even when the main converter 11 intermittently oscillates.

<Modification 2 of Embodiment>
Modification 2 of the embodiment will be described below. In addition, in the modified example 2 of the embodiment, the same reference numerals are given to the same components as in the embodiment, and the description thereof is omitted. The power supply device 1 according to Modification 2 of the embodiment also corrects the second voltage output from the sub-converter 12 based on the first voltage output from the main converter 11 without using the above-described second correspondence information. do. However, the configuration of the power supply device 1 according to Modification 2 of the embodiment is different from the configuration of the power supply device 1 according to Modification 1 of the embodiment.

FIG. 7 is a diagram showing an example of the configuration of the power supply device 1 according to Modification 2 of the embodiment. The duty detection circuit 14 according to Modification 1 of the embodiment includes a voltage dividing circuit 143, a switching element S3, a resistor R3, and a resistor R4 in addition to the configuration shown in FIG. Note that the duty detection circuit 14 may be configured to include other circuit elements, other circuits, and other devices as long as the functions of the power supply device 1 described below are not impaired.

The voltage dividing circuit 143 is supplied with the aforementioned reference voltage from the sub-converter 12 . The voltage dividing circuit 143 divides the magnitude of the reference voltage supplied from the sub-converter 12 into predetermined magnitudes. The voltage dividing circuit 143 outputs the divided reference voltage to the non-inverting input terminal of the comparator 142 . That is, in Modification 2 of the embodiment, the sub-converter 12 outputs the reference voltage to the non-inverting input terminal via the voltage dividing circuit 143 . Note that the power supply device 1 according to Modification 2 of the embodiment may be configured without the voltage dividing circuit 143 . In this case, the magnitude of the reference voltage output from the sub-converter 12 is matched with the predetermined magnitude by some method.

The switching element S3 is an NPN transistor in the example shown in FIG. The switching element S1 may be a PNP transistor instead of an NPN transistor, or may be another switching element such as a field effect transistor. In the following, for convenience of explanation, the state in which current flows between the emitter and collector of the switching element S3 is referred to as the ON state of the switching element S3. For convenience of explanation, the state in which no current flows between the emitter and the collector of the switching element S3 will be referred to as the OFF state of the switching element S3.

The emitter of the switching element S3 is grounded through the transmission line. A collector of the switching element S3 is connected to one end of the resistor R3 via a transmission line. Also, the other end of the resistor R3 is connected to one end of the resistor R4 via a transmission line. Also, the other end of the resistor R4 is connected to the base of the switching element S3 via a transmission line. Also, the transmission line connecting the resistors R3 and R4 is connected to the transmission line connecting the sub-converter 12 and the voltage dividing circuit 143 via the transmission line. A transmission line connecting the resistor R4 and the base is connected to a transmission line connecting the comparator 142 and the control section 16 via the transmission line.

In the power supply device 1 according to Modification 2 of the embodiment, the duty detection circuit 14 shown in FIG. 7 and the control section 16 constitute a correction circuit 20B.

Here, in the duty detection circuit 14 shown in FIG. 7, when the third voltage output from the comparator 142 is the H level voltage, the state of the switching element S3 is the ON state. On the other hand, in the duty detection circuit 14 shown in FIG. 7, when the third voltage output from the comparator 142 is an intermediate voltage between the H level and the L level, the state of the switching element S3 is the OFF state. This can be achieved by adjusting the resistance value of resistor R4.

When switching element S3 is in the OFF state, no current flows from the transmission line connecting sub-converter 12 and voltage dividing circuit 143 between the collector and emitter of switching element S3.

On the other hand, when the switching element S3 is in the ON state, a current corresponding to the resistance value of the resistor R3 flows from the transmission path connecting the sub-converter 12 and the voltage dividing circuit 143 between the collector and the emitter of the switching element S3. flows. As a result, the load on sub-converter 12 increases.

Utilizing this, in the power supply device 1 according to the modification 2 of the embodiment, the voltage is supplied from the voltage detection circuit 15 to the control unit 16 regardless of whether the main converter 11 undergoes full oscillation or intermittent oscillation. The correlation between the second voltage that is applied and the input voltage that is output from the DC power supply 10 can be matched with the correlation indicated by the above-described first correspondence information. This can be accomplished by adjusting the resistance of resistor R3. As a result, even when intermittent oscillation occurs in the main converter 11, the power supply device 1 (or the correction circuit 20B) according to the modification 2 of the embodiment can improve the accuracy of the control performed based on the second voltage. can be improved. For example, the control unit 16 can accurately estimate the magnitude of the input voltage output from the DC power supply 10 . As a result, the power supply device 1 can accurately control the first voltage output from the main converter 11 even when the main converter 11 intermittently oscillates.

Note that the power supply device 1 described above may be mounted on an electric vehicle, or may be mounted on another device driven by the first voltage.
Moreover, each of the correction circuit 20, the correction circuit 20A, and the correction circuit 20B described above may be applied to other devices instead of the switching power supply device such as the power supply device 1. FIG.

In addition, the reason why the intermittent oscillation occurs in the main converter 11 described above is that the period during which the main converter 11 is driven and the period during which the main converter 11 is not driven are cyclically. means repeated. The period during which the main converter 11 is driven is the period during which the state of the switching element included in the main converter 11 is periodically switched between the ON state and the OFF state. Further, while the main converter 11 is driven, the frequency at which the state of the switching element included in the main converter 11 is switched between the ON state and the OFF state is the drive frequency of the drive circuit 13 . On the other hand, the period during which the main converter 11 is driven is the period during which the switching element is kept off.

Further, the fact that the main converter 11 fully oscillates as described above is due to the fact that in the main converter 11, the states of the switching elements included in the main converter 11 are periodically switched between the ON state and the OFF state. means that Then, when the main converter 11 is fully oscillated, the frequency at which the state of the switching element switches between the ON state and the OFF state is the drive frequency of the drive circuit 13 .

As described above, the correction circuit according to the embodiment (the correction circuit 20 and the correction circuit 20A in the example described above) includes the main converter that converts the input voltage and supplies power to the load, and the main converter (described above). In the example described above, the sub-converter (the above In the example described in , the sub-converter 12) is provided, and based on the first voltage generated by the main converter, the second voltage generated by the sub-converter (in the example described above, the voltage detection circuit 15 Detected second voltage) is corrected. This allows the correction circuit to accurately control the first voltage output from the main converter even when intermittent oscillation occurs in the main converter.

The correction circuit also includes a filter (filter 141 in the example described above) that filters the first voltage generated by the main converter, and a difference between the first voltage filtered by the filter and the reference voltage. The second voltage generated by the sub-converter is corrected based on the oscillation state detection circuit (comparator 142 in the example described above) that outputs the third voltage and the third voltage output from the oscillation state detection circuit. and a controller (in the example described above, the controller 16).

Further, in the correction circuit, the control unit selects the third voltage output from the oscillation state detection circuit from the correspondence information in which the input voltage and the second voltage are associated with each voltage range including the third voltage. Arrangements may be used to select correspondence information for the included voltage range and to correct the second voltage generated by the sub-converter based on the selected correspondence information.

In the correction circuit, the transmission line connecting the sub-converter and the control unit (the transmission line EL1 in the example described above) is provided with a switching element (the In the example, the switching element S2) is provided, and the switching element performs switching between the transmission line and the ground according to the signal, and the control unit controls the third voltage output from the oscillation state detection circuit to be a predetermined value. Arrangements may be used to correct the second voltage generated by the sub-converter by changing the state of the switching element to the ON state if it falls within the voltage range.

As described above, the embodiments of the present invention have been described in detail with reference to the drawings. may be

DESCRIPTION OF SYMBOLS 1... Power supply device 10... DC power supply 11... Main converter 12... Sub-converter 13... Drive circuit 14... Duty detection circuit 15... Voltage detection circuit 16... Control part 20... Correction circuit 20A... Correction Circuit 20B Correction circuit 141 Filter 142 Comparator 143 Voltage dividing circuit EL1 Transmission line R1, R2, R3, R4 Resistor S1, S2, S3 Switching element

Claims (5)

a main converter that converts the input voltage to power the load;
a sub-converter that powers one or more other circuits, including a drive circuit that drives the main converter;
with
correcting the second voltage generated by the sub-converter based on a third voltage corresponding to the difference between the first voltage generated by the main converter and the reference voltage supplied from the sub-converter;
The first voltage is a high-frequency pulse voltage before being smoothed,
correction circuit. a filter for filtering the first voltage produced by the main converter;
an oscillation state detection circuit that outputs the third voltage according to the difference between the first voltage filtered by the filter and the reference voltage;
a control unit that corrects the second voltage generated by the sub-converter based on the third voltage output from the oscillation state detection circuit;
2. The correction circuit of claim 1, comprising: The control unit selects the third voltage output from the oscillation state detection circuit from correspondence information in which the input voltage and the second voltage are associated for each voltage range including the third voltage. selecting the corresponding information for the included voltage ranges, and correcting the second voltage generated by the sub-converter based on the selected corresponding information;
3. A correction circuit according to claim 2. A transmission line connecting the sub-converter and the control unit includes a switching element that performs switching according to a signal from the control unit,
The switching element performs switching between the transmission line and ground according to the signal,
When the third voltage output from the oscillation state detection circuit is included in a predetermined voltage range, the control unit changes the state of the switching element to an ON state, thereby changing the third voltage generated by the sub-converter. correcting the second voltage;
3. A correction circuit according to claim 2. the main converter;
the sub-converter;
a correction circuit according to any one of claims 1 to 4;
power supply.

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