Overcurrent protection circuit, dc/dc converter and power management chip

Abstract

The application relates to an overcurrent protection circuit, a DC / DC converter and a power management chip. The overcurrent protection circuit includes: a first power tube, a second power tube, an inductor, an inverter, a feedback signal comparator, a controller, a timing control module, and a minimum on-time comparison module; wherein, the timing control module is used for When the first power tube is turned on, the timing signal is output; the minimum on-time comparison module receives the timing signal and the processing signal output by the inverter; wherein, the minimum on-time comparison module obtains the first power tube conduction signal based on the processing signal. The on-time, and the timing time is obtained based on the timing signal, and according to the time comparison result of the first power tube on-time and the timing time, the output control signal is selected based on the processing signal or the timing signal; the control signal is used to indicate that the corresponding power tube is on or due. The application can avoid the oversaturation of the inductor current and improve the safety of the circuit.

Description

technical field [0001] The present application relates to the technical field of power management, in particular to an overcurrent protection circuit, a DC / DC converter and a power management chip. Background technique [0002] DC / DC (Direct current-Direct current converter, direct current to direct current) converters are applied to the power management chip side of electronic products. The converter often only integrates the corresponding power tube and control circuit. The inductor on the converter is charged and discharged during the DC / DC step-up voltage conversion process to improve the conversion efficiency and achieve small loss. Large inductors and capacitors are required outside the chip. , often at the uH (microhenry) level, which will result in higher BOM (Bill of Material, bill of materials) costs, and the extra pins will not be properly utilized, resulting in the limitation of DC / DC conversion circuits in the field of power supply applications. The turn-on tim...

AI Technical Summary

Problems solved by technology

[0002] DC / DC (Direct current-Direct current converter, direct current to direct current) converters are applied to the power management chip side of electronic products. The converter often only integrates the corresponding power tube and control circuit. The inductor on the converter is charged and discharged during the DC / DC step-up voltage conversion process to improve the conversion efficiency and achieve small loss. Large inductors and capacitors are required outside the chip. , often at the uH (microhenry) level, which will result in higher BOM (Bill of Material, bill of materials) costs, and unreasonable use of redundant pins, resulting in limited DC / DC conversion circuits in power supply applications

The turn-on time of the PMOS power tube is determined by the output of the comparator. The traditional voltage comparator has a hysteresis effect. When the inductance value of the inductor is in the uH range, the rising slope of the inductor current is low, and the transmission current of the control path or the comparator The delay has almost no influence on the inductor current, but for the inductance value in the range of nH (nanohenry), the slope of the inductor current is large, and the delay of ns (nanosecond) level will also cause the inductor current to be too large instantaneously. Or in the case of transient changes in the load current, the excessive delay of the control circuit will cause the inductor current to over-current, or even a straight-through situation.

[0003] During the implementation process, the inventors found that there are at least the following problems in the traditional technology: the traditional DC / DC conversion circuit has low safety

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