Power-off brake circuit for DC fan

Patent metadata

Field	Value
Publication number	US-9537432-B2
Application number	US-201414571302-A
Country	US
Kind code	B2
Filing date	Dec 16, 2014
Priority date	Nov 21, 2014
Publication date	Jan 3, 2017
Grant date	Jan 3, 2017

Abstract

The present invention relates to a power-off brake circuit for a DC fan, which comprises a control unit, a motor driver unit, a switch unit, a power-off protection unit, and a brake unit and a brake unit. The control unit is coupled to the motor driver unit, the switch unit, the power-off protection unit. The brake unit is coupled to the motor driver unit and the power-off protection unit. By means of the circuit design of the present invention, the independent brake loop is used to achieve the effects of power-off brake and of the accurate control of rotating speed is improved.

First claim

What is claimed is:

1. A power-off brake circuit for a DC fan, comprising:
a control unit coupled to an operating voltage;
a motor driver unit coupled to the control unit, an input power source, and at least two ends of a motor coil;
a switch unit coupled to the control unit and the input power source;
a power-off protection unit having a first end, a second end, and a third end, wherein the first end of the power-off protection unit is coupled to the switch unit and the control unit, wherein the second end of the power-off protection unit is coupled to the operating voltage, wherein the third end of the power-off protection unit is coupled to the input power source; and
a brake unit having a first end, a second end, and a third end, wherein the first end of the brake unit is coupled to the third end of the power-off protection unit, wherein the second end of the brake unit is coupled to one end of the motor coil, wherein the third end of the brake unit is coupled to a ground such that the second end of the brake unit, one end of the motor coil, and the ground form a brake loop for braking;
wherein when the DC fan powers on, the power-off protection unit receives the operating voltage and is conducted with the switch unit in a switch-on state and the brake unit is switched off,
wherein when the DC fan powers off, the power-off protection unit does not receive the operating voltage and is not conducted with the switch unit in a switch-off state and the brake unit is actuated to brake.

2. The power-off brake circuit for the DC fan according to claim 1 , wherein the motor driver unit has a first switch, a second switch, a third switch, a fourth switch, a first driver, and a second driver, wherein each of the first switch, the second switch, the third switch, and the fourth switch has a first end, a second end, and a third end, wherein the first end of the first switch is coupled to the third end of the second switch and a first end of the motor coil, wherein the first end of the third switch is coupled to the third end of the fourth switch and a second end of the motor coil, wherein the third ends of the first switch and the third switch are coupled to the input power source, wherein the first ends of the second switch and the fourth switch are coupled to the ground, wherein the second ends of the second switch and the fourth switch are coupled to the control unit, wherein one end of each of the first driver and the second driver is coupled to the second ends of the first switch and the third switch, respectively, wherein the other end of each of the first driver and the second driver is coupled to the control unit.

3. The power-off brake circuit for the DC fan according to claim 2 , wherein the first end of the power-off protection unit is coupled to the control unit and one end of the switch unit, wherein the third end of the power-off protection unit is coupled to the input power source and the third ends of the first switch and the third switch.

4. The power-off brake circuit for the DC fan according to claim 3 , wherein the control unit has a plurality of terminals, wherein a first terminal of the control unit is coupled to the other end of the first driver, wherein a second terminal of the control unit is coupled to the other end of the second driver, wherein a third terminal and a fourth terminal of the control unit are coupled to the second ends of the second switch and the fourth switch, wherein a fifth terminal of the control unit is coupled to the first end of the power-off protection unit and one end of the switch unit, wherein a sixth terminal of the control unit is coupled to the operating voltage.

5. The power-off brake circuit for the DC fan according to claim 2 , further comprising a protection unit and a filter unit, wherein one end of the protection unit is electrically coupled to the input power source and one end of the switch unit, wherein the other end of the protection unit is electrically coupled to one end of the filter unit, wherein the other end of the filter unit is electrically coupled to the first end of the brake unit and the third end of the first switch.

6. The power-off brake circuit for the DC fan according to claim 5 , further comprising a Hall device which is electrically coupled to the fifth terminal of the control unit and the first end of the power-off protection unit.

7. The power-off brake circuit for the DC fan according to claim 1 , wherein the first switch and the third switch are PMOS transistors, wherein the second switch and the fourth switch are NMOS transistors.

Assignees

• Asia Vital Components Co Ltd

Inventors

• Huang Po-Sheng

Classifications

• H02P3/12 Primary

  by short-circuit or resistive braking · CPC title

• H02P7/04

  by means of a H-bridge circuit · CPC title

• H02H7/0838

  with H-bridge circuit · CPC title