发明名称 |
Method and apparatus for controlling power transfer in a flyback converter by modulating the power switch off time during transient conditions |
摘要 |
A method of controlling a flyback DC-DC converter includes using a primary control loop to monitor an auxiliary winding of a transformer for determining the amount of energy being transferred to a load. The voltage in the auxiliary winding is induced by current flowing in the secondary winding of the transformer. The primary control loop disables and enables the turning on of a power switch for driving the primary winding of the transformer, and detects the zero-crossing. The duration that the power switch is turned on is established by a secondary control loop using the output voltage for turning off the power switch for a new off phase. The flyback DC-DC converter further includes a fixed frequency oscillator having a frequency lower than the self-oscillating frequency of the converter. The power transferred from the primary circuit to the secondary circuit of the flyback transformer is controlled by introducing a delay on the turn-on instant of the power switch. This is with respect to a turn-on command generated during a self-oscillating functioning phase regardless of the mode of control of the converter. The turn-on command is based upon a zero crossing, a fixed frequency functioning phase, a rising edge of the signal generated by the oscillator, and as a function of the input variables of the primary and secondary control loops.
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申请公布号 |
US6118675(A) |
申请公布日期 |
2000.09.12 |
申请号 |
US19990413996 |
申请日期 |
1999.10.07 |
申请人 |
STMICROELECTRONICS S.R.L. |
发明人 |
LIONETTO, ANTONIO;OCCHIPINTI, LUIGI;SPAMPINATO, SERGIO TOMMASO;CAPONETTO, RICCARDO |
分类号 |
H02M3/28;H02M1/00;H02M1/36;H02M3/335;(IPC1-7):H02M3/335 |
主分类号 |
H02M3/28 |
代理机构 |
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代理人 |
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主权项 |
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地址 |
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