Switching converter for constant turn-on time control and automatic calibration method thereof

Abstract

The invention discloses a switching converter for constant turn-on time control as well as a controller, a control method and an automatic calibration method thereof. The switching converter comprises a main transistor, a turn-on time control circuit for determining the turn-on time of the main transistor, and a logic circuit for controlling the main transistor. The automatic calibration method comprises the steps of: generating periodic clock signals with a preset duty cycle; providing a first voltage and a second voltage to the turn-on time control circuit, so that the turn-on time control circuit generates turn-on time control signals based on the first voltage and the second voltage; providing the clock signals and the turn-on time control signals to the logic circuit, so that the logic circuit generates switching control signals based on the clock signals and the turn-on time control signals; comparing the duty cycle of the switching control signals with the duty cycle of the clock signals to generate correction code signals; and adjusting circuit parameters in the turn-on time control circuit based on the correction code signals.

Description

technical field [0001] The invention relates to an electronic circuit, in particular to a switching converter controlled by constant on-time and its controller, control method and automatic calibration method. Background technique [0002] Constant on-time control (COT control, constant on-time control) has been well applied in the power supply field due to its superior load transient response, simple internal structure and smooth operation mode switching. [0003] figure 1 It is a block diagram of an existing synchronous buck converter using constant on-time control, where the on-time control circuit usually generates an on-time control signal COT based on the input voltage Vin and the output voltage Vout to determine the conduction of the upper transistor M1 time. The comparison circuit compares the output voltage Vout with the reference voltage Vref to provide a comparison signal SET. The logic circuit generates a switch control signal CTRL according to the on-time con...

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Problems solved by technology

[0004] In the mass-manufacturing process, process deviations (such as deviations in resistance values, capacitance values, or comparator delays) will affect the above-mentioned on-time control circuit, causing converters with the same design to operate under the same input and output voltage conditions. The resulting turn-on time is different, which affects the consistency of the product

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