| US 7,456,622 B2 | ||
| Circuit for starting up a synchronous step-up DC/DC converter and the method thereof | ||
| Mao Chuan Chien, Hsinchu (Taiwan); Chu Yu Chu, Hsinchu (Taiwan); and Yu Min Sun, Hsinchu (Taiwan) | ||
| Assigned to Advanced Analog Technology, Inc., Taiwan (China) | ||
| Filed on Apr. 10, 2007, as Appl. No. 11/783,564. | ||
| Claims priority of application No. 96108690 A (TW), filed on Mar. 14, 2007. | ||
| Prior Publication US 2008/0224673 A1, Sep. 18, 2008 | ||
| Int. Cl. G05F 1/575 (2006.01); G05F 1/618 (2006.01) | ||
| U.S. Cl. 323—284 [323/224] | 11 Claims |
| 1. A circuit for starting up a synchronous step-up DC/DC converter, the circuit connected to a voltage source through an inductor
and comprising:
a P-type power transistor including a parasitic diode, one end of the P-type power transistor providing an oscillator with
power;
an N-type power transistor connected to the P-type power transistor; and
a controller electrically connected to the oscillator, the controller including a delay unit and a logic unit, wherein the
logic unit disables the N-type power transistor and enables the P-type power transistor upon start-up, and the delay unit
disables the P-type power transistor and enables the N-type power transistor in a period after start-up.
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