llc series resonant joint controller

Abstract

The invention relates to a combined controller of an LLC series resonant converter. It includes a bridge circuit, the bridge circuit drives a resonant network, a transformer, a frequency modulation controller, a duty cycle controller, an output rectifier circuit, an output voltage detection circuit and an output current detection circuit, the resonant network is connected in series with the primary side of the transformer, and the resonant The network is connected in series between the midpoint of the bridge circuit and the transformer, the filter capacitor is connected in parallel at the output end, the output voltage sampling circuit samples the output voltage value and sends it to the frequency modulation controller and the duty ratio controller, and the output current detection circuit samples the output current value at the same time sent to the duty cycle controller. The driving waveform is comprehensively adjusted by the frequency modulation controller and the duty cycle controller and sent to the bridge circuit for voltage regulation. The invention realizes the low-frequency narrow starting pulse, reduces the impact current of the power switch when starting; realizes the low-frequency narrow starting pulse work under no-load, deep current limiting and short-circuit working conditions, reduces the impact current of the power switch, and reduces the driving loss.

Description

technical field [0001] The invention relates to a combined controller of an LLC series resonant converter, in particular to a controller of an LLC series resonant converter which uses a frequency adjustment controller combined with a duty cycle controller to provide a driving signal. Background technique [0002] LLC is a commonly used topology in the industry, because the most important components in the topology are resonant inductor (L), excitation inductance (L) and resonant capacitor (C), so this topology is called LLC in the industry. [0003] Such as figure 1 As shown, the LLC series resonant converter adopts a full-bridge structure, which includes a half-bridge circuit 110 composed of a pair of power switches Q1 and Q2 to drive a resonant network 120, which consists of a resonant capacitor Cr and a resonant inductor Lr It is composed of the excitation inductance Lm of the primary side of the transformer TX, and Lr may also be the leakage inductance form of the trans...

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Problems solved by technology

The former will increase the driving loss and increase the additional stress of the driving circuit, while the latter wil...

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