US 6,982,531 B2
Driving circuit for switches of direct current fan motor
Lain-ken Lin, Changhua (Taiwan); Sans Chang, Taipei (Taiwan); Magellan Chiu, Taichung (Taiwan); and Wen-shi Huang, Taoyuan (Taiwan)
Assigned to Delta Electronics, Inc., (Taiwan)
Filed on Aug. 29, 2003, as Appl. No. 10/651,587.
Claims priority of application No. 92117425 A (TW), filed on Jun. 26, 2003.
Prior Publication US 2004/0264948 A1, Dec. 30, 2004
Int. Cl. H02P 3/18 (2006.01)
U.S. Cl. 318—254 22 Claims
OG exemplary drawing
 
1. A driving circuit for switches of direct current fan motor comprising:
a plurality of switches driven by a first pulse width modulation (PWM) signal and a second PWM signal;
a first control circuit electrically connected with at least one switch driven by the first PWM signal, and driven by a third PWM signal; and
a second control circuit electrically connected with at least one switch driven by the second PWM signal, and driven by a fourth PWM signal;
wherein, when the first PWM signal is at a low level, the switches driven by the first PWM signal are in an OFF state, and the third PWM signal drives the first control circuit and locks the switches driven by the first PWM signal to an OFF state; and when the second PWM is at a low level, the switches driven by the second PWM are in an OFF state, and the fourth PWM signal drives the second control circuit and locks the switches driven by the second PWM signal to an OFF state.