A compound dcdc circuit

Abstract

The present invention relates to the field of circuit technology, in particular to a composite DCDC circuit, which includes a switch device group connected between the input terminal and the ground terminal of the working circuit; a drive control unit, the input terminal of the drive control unit is connected to the working circuit The output terminal is used to generate a PWM drive signal under the action of the voltage signal output by the working circuit and the switching control signal; the compensation unit, the input terminal of the compensation unit is connected to the output terminal of the drive control unit, and is used to adjust and compensate the range of the PWM drive signal; The loop compensation unit, the input end of the loop compensation unit is connected to the output end of the compensation unit; the adjustment unit, the input end of the adjustment unit is connected to the output end of the compensation unit, and is used to adjust the gain of the PWM driving signal. The beneficial effect of the technical solution of the present invention is that: a double-loop structure is adopted, a compensation loop is added without destroying the stability of the original loop, and the precision of the output voltage is improved.

Description

technical field [0001] The invention relates to the technical field of circuits, in particular to a composite DCDC (Direct Current DC power converted to DC power) circuit. Background technique [0002] With the wide application of portable electronic products in the fields of communication, computer and consumer electronic products, the demand for power management integrated chips continues to rise. The DCDC switching power supply is widely used due to its advantages of wide input voltage range, large output current, small quiescent current, and wide output load range. DCDC switching power supply has a variety of control modes. According to the sampling signal, it can generally be divided into voltage mode and current mode. The voltage mode performs negative feedback by sampling the output voltage; the current mode performs negative feedback by sampling the input current and output voltage. [0003] In the prior art, COT (constant on-time mode) has a fast response speed, b...

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Problems solved by technology

[0003] In the prior art, COT (constant on-time mode) has a fast response speed, but it needs to generate a voltage ripple from the ESR resistor in phase with the inductor current to stabilize the loop. For ceramic capacitors with extremely small ESR Occasionally, stability is more difficult; if a single loop is used, the gain of the comparator is limited; because the comparator requires high speed, the size of the input tube cannot be too large to reduce the parasitic capacitance, so there is a large error itself; the first phase comparison point is The high point of the feedforward capacitor (the boost architecture is the high point, and the buck architecture is the low point), so the comparison point of the comparator itself has an error, so when the load is small and the ripple is small, the output voltage value changes not big

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