CN-115411940-B - Voltage converter mode switching circuit and method for tracking load current

CN115411940BCN 115411940 BCN115411940 BCN 115411940BCN-115411940-B

Abstract

The voltage converter mode switching circuit and method for tracking load current are characterized by comprising a mode control unit and an adjusting unit, wherein the mode control unit is used for generating a mode control signal and controlling the voltage converter to switch between a boosting mode and a step-down mode based on the mode control signal, and the adjusting unit is connected with the mode control unit and used for acquiring an output signal of an error comparator in the voltage converter and generating a feedback current so as to adjust the inversion level of the mode control signal in the mode control unit. The invention has ingenious conception, reasonable and effective method, fully considers various different load environments of the voltage converter, and fully ensures the stability of output voltage under different environments.

Inventors

JIN ZHENGYANG
YU XIANG
XIAO FEI

Assignees

圣邦微电子(苏州)有限责任公司

Dates

Publication Date: 20260508
Application Date: 20220812

Claims (8)

1. A voltage converter mode switching circuit for tracking load current, comprising: The voltage converter mode switching circuit comprises a mode control unit and a regulating unit, wherein, The mode control unit comprises a first current source, a second current source, a first voltage dividing resistor, a second voltage dividing resistor, a current switching tube and an operational amplifier, wherein the first voltage dividing resistor R1 and the second voltage dividing resistor R2 are connected in series and then connected between an input voltage Vin and the ground, the first current source I0 is connected in parallel at two ends of the second voltage dividing resistor R2, one end of the second current source I1 is connected with a high-voltage end of the second voltage dividing resistor R2, the other end of the second current source I1 is connected with a drain electrode of the current switching tube, a source electrode of the current switching tube is grounded, a grid electrode of the current switching tube is connected with an output end of the operational amplifier, a positive phase input end of the operational amplifier is connected with a reference voltage Vref, a negative phase input end of the operational amplifier is connected with a connection point between the first voltage dividing resistor R1 and the second voltage dividing resistor R2 to receive a resistor voltage dividing V-, and an output end of the operational amplifier is controlled to switch between a boosting mode and a step-down mode based on the mode control signal; The adjusting unit comprises a reference subunit, a comparison subunit and a mirror image subunit, wherein the reference subunit is used for receiving the input voltage Vin to generate a comparison reference voltage Vref1 and inputting the comparison reference voltage Vref1 into the comparison subunit, the comparison subunit is connected with the reference subunit and the mirror image subunit and used for receiving the comparison reference voltage, acquiring an output signal of an error comparator in the voltage converter and generating a feedback current based on a comparison result of the comparison reference voltage and the comparison result, and the mirror image subunit is connected with the mode control unit and used for mirroring the feedback current into the mode control unit to adjust the turnover level of a mode control signal in the mode control unit.
2. A voltage converter mode switching circuit for tracking load current as recited in claim 1, wherein: the reference subunit comprises a reference tube Mp1 and a reference current source Iref; The source electrode of the reference tube Mp1 is connected with the power supply voltage, and the drain electrode and the grid electrode are grounded through the reference current source Iref; The drain and gate of the reference tube Mp1 serve as the output of the reference subunit, and provide a comparison reference voltage Vref1 for the comparison subunit.
3. A voltage converter mode switching circuit for tracking load current as recited in claim 2, wherein: the comparison subunit comprises a first input tube, a second input tube, a current mirror and a bridging resistor; the current mirror comprises a MOS tube connected in a mirror image mode and two identical mirror image current sources; the drains of the first input tube and the second input tube are respectively connected to the drains of the two MOS tubes, and the drains of the first input tube and the second input tube are respectively connected to the two mirror image current sources; the grid electrode of the first input tube is connected with the comparison reference voltage Vref1, and the grid electrode of the second input tube is connected with the output signal of the error comparator; The cross-over resistor is connected between the source electrode of the first input tube and the source electrode of the second input tube, and the drain electrode of the first input tube is used as the output of the comparison subunit to be connected with the mirror image subunit.
4. A voltage converter mode switching circuit for tracking load current as recited in claim 3, wherein: The output end of the mirror image subunit is electrically connected with the connection of the first voltage dividing resistor R1 and the second voltage dividing resistor R2 in the mode control unit.
5. A voltage converter mode switching circuit for tracking load current as recited in claim 4, wherein: the feedback current is ; Wherein, the For the current mirror proportion of the mirror sub-unit, For the output voltage of the error comparator, For the crossover resistance.
6. A voltage converter mode switching circuit for tracking load current as recited in claim 5, wherein: When the input voltage Vin gradually decreases, the inversion level of the mode control signal in the mode control unit is ; Wherein, the Rated output current for the first current source; When the input voltage Vin gradually rises, the inversion level of the mode control signal in the mode control unit is ; Wherein, the Is the rated output current of the second current source.
7. A voltage converter mode switching circuit for tracking load current as recited in claim 4, wherein: the inversion level of the mode control signal in the mode control unit And Linear relation with the load current of the voltage converter; The lighter the load of the subsequent stage of the voltage converter is, the inversion level is And The smaller the value of (c).
8. A method for switching modes of a voltage converter tracking load current, comprising the steps of: the method is implemented with a voltage converter mode switching circuit tracking load current as claimed in any one of claims 1-7.

Description

Voltage converter mode switching circuit and method for tracking load current Technical Field The present invention relates to the field of integrated circuits, and more particularly, to a voltage converter mode switching circuit and method for tracking load current. Background A direct current-to-direct current voltage converter (DC-to-DC converter) is a common power conversion circuit, and is capable of converting a direct current power supply into direct current of different voltages or a stable voltage similar to the direct current for output. The high-voltage power supply has the advantages of wide power range, stable output voltage and the like, and is widely applied to various fields. In the prior art, in order to provide stable output voltage for a later stage load under different power input conditions, a main current direct current-direct current voltage converter can work in different modes of Step-up or Step-down, and the output voltage is regulated by reasonably regulating the switching state of a power tube. In general, the circuit structures such as the mode control unit can judge the working mode of the voltage converter according to the magnitude of the input voltage, and realize reasonable switching of the voltage converter between the step-up mode and the step-down mode. Therefore, the design of the flip level of the mode control signal plays a crucial role in the operation performance of the voltage converter. However, in the current voltage converter circuit, since the voltage converter may work in various environments such as no-load, light-load and heavy-load, it is difficult to keep the voltage converter in a reasonable condition to realize mode switching in various environments due to the pre-calculated flip level. This causes, for example, that in a light load or no-load state, the voltage converter switches to the boost mode in advance, which causes unnecessary waste of power supply and large impact on the light load circuit, and even makes it difficult to ensure the safety of the subsequent circuit. In view of the foregoing, a new mode switching circuit and mode switching method for a voltage converter are needed. Disclosure of Invention In order to solve the defects in the prior art, the invention aims to provide a voltage converter mode switching circuit and a voltage converter mode switching method for tracking load current, which ensure that the voltage converter can keep reasonable working mode switching in different load environments by adjusting the magnitude of a turnover level of a mode control signal approximately linearized along with the magnitude of the load current. The invention adopts the following technical scheme. The invention relates to a mode switching circuit of a voltage converter for tracking load current, which comprises a mode control unit and an adjusting unit, wherein the mode control unit is used for generating a mode control signal and controlling the voltage converter to switch between a boosting mode and a step-down mode based on the mode control signal, and the adjusting unit is connected with the mode control unit and used for acquiring an output signal of an error comparator in the voltage converter and generating a feedback current so as to adjust the inversion level of the mode control signal in the mode control unit. The mode control unit comprises a first current source, a second current source, a first voltage dividing resistor, a second voltage dividing resistor, a current switching tube and an operational amplifier, wherein the first voltage dividing resistor R1 and the second voltage dividing resistor R2 are connected in series and then connected between an input voltage Vin and the ground, the first current source I0 is connected in parallel to two ends of the second voltage dividing resistor R2, one end of the second current source I1 is connected with a high-voltage end of the second voltage dividing resistor R2, the other end of the second current source I1 is connected with a drain electrode of the current switching tube, a source electrode of the current switching tube is grounded, a grid electrode of the current switching tube is connected with an output end of the operational amplifier, a positive-phase input end of the operational amplifier is connected with a reference voltage Vref, and a negative-phase input end of the operational amplifier is connected with a connection point between the first voltage dividing resistor R1 and the second voltage dividing resistor R2 to receive a resistor voltage dividing V-, and an output end outputs a mode control signal. The regulation unit comprises a reference subunit, a comparison subunit and a mirror image subunit, wherein the reference subunit is used for receiving an input voltage Vin to generate a comparison reference voltage Vref1 and inputting the comparison reference voltage Vref1 into the comparison subunit, the comparison subunit is connected with the reference subunit and the mi