Vrms and rectified current sense full-bridge synchronous-rectification integrated with PFC
First Claim
1. A synchronous full bridge rectification circuit having an AC input and a DC output, the circuit comprising:
- a boost inductor with a first node coupled to the AC signal;
a full bridge rectifier circuit functionally connected between a second node of the boost inductor and the DC output, the full wave rectifier circuit comprising at least two controllable switches;
means for sensing current in the DC output and in the charging paths of the boost inductor on both half cycles of the AC input; and
a controller arranged to receive the AC signal, the sensed currents, and the DC output, wherein the controller outputs signals to control the at least two controllable switches in a manner where the PF of the synchronous full bridge rectifier approaches unity with respect to the AC source, wherein the controller output signal are separate and independent signals, one such signal to each of the at least two controllable switches, wherein in one half cycle of the AC signal, one controllable switch is driven on and the other is intermittently driven on and off, and wherein during the other half cycle of the AC signal the other controllable switch is driven on and the one controllable switch is intermittently driven on and off.
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Accused Products
Abstract
A synchronous full bridge rectifier is controlled to provide a power factor near unity. The full bridge rectifiers are transistors each with a controlling input. The AC input signal and currents within the circuit are sensed and sent to a controller. In response, the controller output control signals to turn on/off the rectifying MOSFETS on a timely basis to form a power factor of near one with respect to the AC input signal. The full wave rectifier is made of N-channel MOSFET'"'"'s, some with fast body diodes. The MOSFET'"'"'s are rectifiers and PFC control elements. The result is a one stage synchronous rectifier with PFC. A solid state precision analog differential amplifier senses the AC line waveform and high frequency current transformers sense the currents. The controller accepts the inputs of the amplifier and the sensed currents and outputs control signals that turn on and off the four MOSFET'"'"'s. The timing of turning on/off is arranged so that the current drawn from the AC source is sinusoidal and matches the phase of the sinusoidal AC source.
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Citations
8 Claims
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1. A synchronous full bridge rectification circuit having an AC input and a DC output, the circuit comprising:
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a boost inductor with a first node coupled to the AC signal; a full bridge rectifier circuit functionally connected between a second node of the boost inductor and the DC output, the full wave rectifier circuit comprising at least two controllable switches; means for sensing current in the DC output and in the charging paths of the boost inductor on both half cycles of the AC input; and a controller arranged to receive the AC signal, the sensed currents, and the DC output, wherein the controller outputs signals to control the at least two controllable switches in a manner where the PF of the synchronous full bridge rectifier approaches unity with respect to the AC source, wherein the controller output signal are separate and independent signals, one such signal to each of the at least two controllable switches, wherein in one half cycle of the AC signal, one controllable switch is driven on and the other is intermittently driven on and off, and wherein during the other half cycle of the AC signal the other controllable switch is driven on and the one controllable switch is intermittently driven on and off. - View Dependent Claims (2, 3, 4, 5, 6)
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7. A method for synchronously full wave rectifying an AC input to provide a DC output, the method comprising:
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inductively reacting to current traveling from the AC input to a full bridge rectifier circuit, the full bridge having at least two controllable switches; coupling the output from the full wave rectifier circuit to the DC output; sensing current in the DC output; sensing the charging currents to the inductive reactance; sensing the AC signal and sending the sensed AC and the sensed currents to a controller; and wherein in response to the received signals, the controller turns on and off the at least two controllable switching devices in a manner where the PF of the synchronous full bridge rectifier approaches unity with respect to the AC source wherein the controller output signal are separate and independent signals, one such signal to each of the at least two controllable switches, wherein in one half cycle of the AC signal, one controllable switch is driven on and the other is intermittently driven on and off, and wherein during the other half cycle of the AC signal the other controllable switch is driven on and the one controllable switch is intermittently driven on and off. - View Dependent Claims (8)
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Specification