Low-power-consumption load current detection circuit applied to PWM DC-DC converter

Abstract

The invention discloses a low-power-consumption load current detection circuit applied to a PWM DC-DC converter, which belongs to the technical field of microelectronics. The circuit comprises a peakcurrent sensing module, a sampling hold circuit, an analog-to-digital conversion module and the like. A peak current detection module, a sampling hold circuit and an analog-to-digital conversion module are adopted, the input end of the peak current detection module is connected to a drain electrode of a freewheeling tube needing to be detected through a switch tube, then the output end of the peakcurrent detection module is connected with the input end of the sampling hold circuit, and the output end of the sampling hold circuit is connected with the input end of the analog-to-digital conversion circuit. The sampling hold circuit obtains a stable peak current signal through a switch capacitor, the stable peak current signal is converted into a digital signal VS [0: 3] through an analog-to-digital conversion module (3), and the change of the load current is shown through the change of the VS [0: 3] signal.

Description

technical field [0001] The invention belongs to the technical field of integrated circuit design and relates to the design of a load current detection circuit applied to PWM DC-DC. Background technique [0002] The load current detection (Load Current Detection) circuit in the DC-DC converter is often used to monitor the change of the load current. Whether it is a current control mode or a multi-modulation voltage control mode, the load current detection circuit is a basic circuit module. . In order to make the processing of the control module more convenient and stable, it is usually also hoped that the change of the load current sampled by the load current detection circuit can be converted into a digital signal. [0003] Common current detection methods for switching power converters include peak current detection (Peak Current Detection) and average current detection (Average Current Detection). Peak current detection is a detection method that reflects the magnitude o...

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Problems solved by technology

[0005] like figure 1 As shown, the traditional peak current detection circuit is also from V SW The difference is that the traditional peak current detection circuit is mostly used in the current mode control loop, and an additional compensation circuit is required. To apply the traditional peak current detection circuit to the voltage mode control loop, the problem to be solved is how to Obtain a stable current sampling signal, and facilitate subsequent processing while obtaining a stable signal during sampling

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