Patent ID: 11880217
Assignee: CHENGDU MONOLITHIC POWER SYSTEMS CO., LTD.
Field: Electrical machinery, apparatus, energy (Electrical engineering)
Classification: CPC G  H | IPC G  H

Claim 6:
7. A power management circuit, comprising:
a power input pin coupled a power source to receive an input voltage;
a system output pin configured to output an output voltage to a load;
a switching node pin coupled to a rechargeable battery through an inductor;
a ground pin;
a first switch having a first terminal, a second terminal and a control terminal, wherein the first terminal is coupled to the system output pin, the second terminal is coupled to the switching node pin, and the control terminal is driven by a first driving signal;
a second switch having a first terminal, a second terminal and a control terminal, wherein the first terminal is coupled to the switching node pin, the second terminal is coupled to the ground pin, and the control terminal is driven by a second driving signal; and
a control circuit configured to control the first switch and the second switch to operate in a buck mode or a boost mode, and wherein the first switch is turned OFF for a constant time, and the second switch is turned ON for the constant time, the control circuit comprising:
a plurality of feedback control circuits configured to provide the plurality of feedback control signals, wherein each of the plurality of feedback control circuits is configured to receive a corresponding feedback signal and a corresponding reference signal and provide a corresponding feedback control signal at a corresponding output terminal based on a difference between the corresponding feedback signal and the corresponding reference signal;
a selection circuit configured to receive the plurality of feedback control signals and select a minimum value among the feedback control signals as a feedback control signal;
an offset voltage generator configured to receive a first current sensing signal indicative of a current flowing through the inductor and provide a DC offset voltage and a second current sensing signal, wherein the second current sensing signal is generated by adding the DC offset voltage on to the first current sensing signal;
a first comparison circuit configured to compare the feedback control signal to the second current sensing signal and provide a first comparison signal at an output terminal;
a constant time generator coupled to the output terminal of the first comparison circuit to receive the first comparison signal and configured to provide a constant time control signal having the constant time; and
a logic circuit configured to generate a first control signal and a second control signal based on the first comparison signal and the constant time control signal.