Power discharge control system

• US 7,839,026 B2
• Filed: 07/28/2008
• Issued: 11/23/2010
• Est. Priority Date: 05/14/2008
• Status: Expired due to Fees

• Current Assignee: Inventec Corporation
• Original Assignee: Inventec Corporation
• Inventors: Huang, Lan, Liu, Shih-Hao
• Primary Examiner(s): Fureman; Jared J
• Assistant Examiner(s): Parries; Dru M
• Application Number:
  US12/220,778
• Publication Number:
  US 20090284081A1
• Time in Patent Office: 848 Days
• Field of Search: 307/99
• US Class Current: 307/99
• CPC Class Codes: H05K 9/0067 Devices for protecting against damage from electrostatic discharge

Abstract

A power discharge control system for eliminating residual voltage of electronic components in an electronic device, is proposed, which includes a control IC for outputting first electrical signals of a first level and a second level respectively corresponding to power on and power off of the electronic device; a power supply for receiving the first electrical signal, and providing or terminating operation power to the electronic component accordingly, and delaying outputting of a second electrical signal equivalent to the first electrical signal level; a logic judgment module connected to the control IC and the power supply for receiving the first and the second electrical signals for executing logic operation process, when at least one of the first and the second electrical signals is at the first level, a third electrical signal of a third level is outputted, when both the first and the second electrical signals are at the second level, a third electrical signal of a fourth level is outputted; and at least a discharge module for receiving the third electrical signal, when the third electrical signal is at the third level, the discharge process is skipped, when the third electrical signal is at the fourth level, the discharge process is executed.

Claims

1. A power discharge control system for eliminating residual voltage of at least an electronic component in an electronic device, comprising:

a control IC for outputting first electrical signals of a first level and a second level respectively corresponding to power on and power off commands of the electronic device;

a power supply electronically connected to the control IC and the at least an electronic component, wherein the power supply receives the first electrical signal outputted by the control IC, so as to accordingly provide or terminate at least an operation power to the at least an electronic component, and delays outputting a second electrical signal which is equivalent to the first electrical signal level;

a logic judgment module coupled to the control IC and the power supply, wherein the logic judgment module receives the first electrical signal outputted by the control IC as well as the second electrical signal outputted by the power supply, executes logic operation process, and outputs a third electrical signal of a third level when at least one of the first electrical signal and the second electrical signal is at the first level and outputs a third electrical signal of a fourth level when both the first electrical signal and the second electrical signal are at the second level; and

at least a discharge module, for receiving the third electrical signal outputted from the logic judgment module, and to determine a discharge process to be skipped when the third electrical signal is at the third level and the discharge process to be executed when the third electrical signal is at the fourth level.

2. The power discharge control system of claim 1, wherein the control IC is a Southbridge IC.

3. The power discharge control system of claim 1, wherein the first level corresponding to the power on command is a high level, and the second level corresponding to the power off command is a low level.

4. The power discharge control system of claim 1, wherein the logic judgment module further comprises:

a first logic judgment unit having a first control terminal, a first end, and a second end, wherein the first control terminal is electrically connected to the control IC for receiving the first electrical signal, the first end is electrically connected to a backup power, and the second end is grounded; and

a second logic judgment unit having a second control terminal, a third end, and a fourth end, wherein the second control terminal is electrically connected to the power supply for receiving the second electrical signal, the third end is electrically connected to the backup power, and the fourth end is grounded.

5. The power discharge control system of claim 4, wherein the first logic judgment unit and the second logic judgment unit are NMOS transistors, the first control terminal and the second control terminal are gates of the NMOS transistors, the first end and the third end are drains of the NMOS transistors, and the second end and the fourth end are sources of the NMOS transistors.

6. The power discharge control system of claim 1, wherein the discharge module comprises:

a dissipative resistor, wherein one end of the dissipative resistor is electrically connected to a branch node formed at electrical connection of the power supply and the electronic component for receiving the operation power; and

a switch unit having a third control terminal, a fifth end, and a sixth end, wherein the third control terminal is electrically connected to the logic judgment module for receiving the third electrical signal outputted therefrom, the fifth end is coupled to another end of the dissipative resistor, the sixth end is grounded, and an electrical connection between the fifth end and the sixth end of the switch unit is cut off when the third electrical signal received by the third control terminal is at the third level and the switch unit is turned on to electrically connect the fifth end and the sixth end for executing the discharge process on residual voltage of the electronic component when the third electrical signal is at the fourth level .

7. The power discharge control system of claim 1, wherein the third level is a low level, and the fourth level is a high level.

8. The power discharge control system of claim 6, wherein the switch unit is an NMOS transistor, a gate of the NMOS transistor is used as the third control terminal for electrically connecting the logic judgment module, a drain of the NMOS transistor is used as the fifth end for electrically connecting the dissipative resistor, and a source of the NMOS transistor is used as the sixth end which is grounded.

9. The power discharge control system of claim 6, wherein the switch unit is an NPN transistor, a base of the NPN transistor is used as the third control terminal for electrically connecting the logic judgment module, a collector of the NPN transistor is used as the fifth end for electrically connecting the dissipative resistor, and an emitter of the NPN transistor is used as the sixth end which is grounded.

10. The power discharge control system of claim 6, wherein the third level is a low level, and the fourth level is a high level.