Pulse with modulation control circuit for a high frequency series resonant AC/DC converter
First Claim
1. A control circuit for an alternating current (AC) to direct current (DC) converter, comprising a delay circuit for introducing a delay in the generation of gating signals for controlled switches of the converter so that zero crossing detection is pre-processed and compensation for inherent delays in circuits used to generate the gating signals is introduced, the delay circuit causing a leading edge of the gating signals to be in phase and synchronized with zero crossings of the AC input voltage to a terminal of the rectifier switches.
4 Assignments
0 Petitions
Accused Products
Abstract
A pulse width modulation control circuit for a high frequency series resonant AC/DC converter suitable for use in computing and network equipment such as personal computers, servers and high-speed routers includes an auxiliary transformer, a zero crossing detector, a delay circuit, a synchronization circuit and an output circuit.
-
Citations
19 Claims
- 1. A control circuit for an alternating current (AC) to direct current (DC) converter, comprising a delay circuit for introducing a delay in the generation of gating signals for controlled switches of the converter so that zero crossing detection is pre-processed and compensation for inherent delays in circuits used to generate the gating signals is introduced, the delay circuit causing a leading edge of the gating signals to be in phase and synchronized with zero crossings of the AC input voltage to a terminal of the rectifier switches.
-
2. A control circuit for an alternating current (AC) to direct current (DC) converter, comprising a delay circuit for delaying first and second converter switch gating signals generated by a zero-voltage crossing detector by a time period:
-
18. A control circuit for an alternating current (AL) to direct current (DC) converter, comprising:
-
a zero-voltage detector circuit for detecting zero crossings of an AC input voltage to the converter; and
a delay circuit for delaying a gating signal for a first switch of the converter during a positive cycle of the AC input voltage to the converter, and for delaying a gating signal for a second switch of the converter during a negative cycle of the AC input voltage, so that zero voltage crossing detection is pre-processed and compensation for converter switching circuit delays is introduced during generation of the respective gating signals, to ensure that the first and second switches are switched at zero crossings of the AC input voltage and cross-conduction between the first and second switches is avoided.
-
-
19. A method of controlling switches in a converter for converting an AC (alternating current) to a DC (direct current) comprising steps of:
-
a) detecting zero-crossings of an AC input voltage to the converter; and
b) after detecting a zero-crossing of the input AC voltage, generating a gating signal for a first switch of the converter during a positive half-cycle of the input voltage to the converter, and generating a gating signal for a second switch of the converter during a negative half-cycle of the input voltage, so that zero voltage crossing detection is pre-processed and compensation for converter switching circuit delays is introduced during generation of the respective gating signals to ensure that the first and second switches are switched at zero crossings of the AC input voltage and cross-conduction between the first and second switches is avoided.
-
Specification