Power supply apparatus

• US 8,089,258 B2
• Filed: 03/19/2010
• Issued: 01/03/2012
• Est. Priority Date: 03/19/2010
• Status: Active Grant

• Current Assignee: 3Y Power Technology, Inc. (FSP Technology Inc.), FSP Technology Inc.
• Original Assignee: 3Y Power Technology, Inc. (FSP Technology Inc.), FSP Technology Inc.
• Inventors: Tsai, Chih-Chang
• Primary Examiner(s): Laxton, Gary L
• Application Number:
  US12/727,254
• Publication Number:
  US 20110227548A1
• Time in Patent Office: 655 Days
• Field of Search: 323/271, 323/272, 323/282, 323/284, 323/285, 323/286, 323/351
• US Class Current: 323/285
• CPC Class Codes: H02J 1/102 being switching converters H02J1/108, H02J1/12 take precedence

Abstract

A power supply apparatus is provided. The power supply apparatus includes two power suppliers coupled in parallel so as to simultaneously supply the electric power required by an electronic product in operation. The power supply apparatus provided by the invention may stably/accurately output the desired DC output voltage to the electronic product, and may further in advance increase a main power generated inside the other power supplier when one of the power suppliers is over voltage, thereby avoiding an oversized voltage drop from occurring in the DC output voltage.

Claims

1. A power supply apparatus, comprising:

a first power supplier, configured for receiving a direct current (DC) input voltage and generating a DC output voltage accordingly, the first power supplier comprising;

a main power generating unit, configured for receiving and converting the DC input voltage so as to generate a main power accordingly;

a first resistor having a first terminal coupled to the main power generating unit and receiving the main power;

an isolation diode having an anode coupled to a second terminal of the first resistor and a cathode outputting the DC output voltage;

a second resistor having a first terminal coupled to the anode of the isolation diode;

a voltage feedback controller, coupled to a second terminal of the second resistor and the main power generating unit, configured for providing a control signal to control the main power generating unit according to a voltage of the second terminal of the second resistor, so as to regulate the main power; and

a current detecting unit, coupled to the first terminal and the second terminal of the first resistor, configured for detecting a current flowing through the first resistor, so as to output an adjustment signal for controlling a voltage of the second terminal of the second resistor substantially equal to a voltage of the cathode of the isolation diode, and thus making the first power supplier stably output the DC output voltage.

2. The power supply apparatus according to claim 1, further comprising:

a second power supplier, configured for receiving the DC input voltage and generating the DC output voltage accordingly,

wherein the DC output voltages respectively generated by the first power supplier and the second power supplier are simultaneously provided to a load.

3. The power supply apparatus according to claim 2, wherein the first power supplier further comprising:

an over voltage detecting unit, coupled to the cathode of the isolation diode and the second terminal of the second resistor, configured for pulling down the voltage of the second terminal of the second resistor when the second power supplier is over voltage, so as to increase a duty cycle of the control signal and thus increasing the main power.

4. The power supply apparatus according to claim 3, wherein the current detecting unit comprises:

a first operational amplifier having a positive input terminal coupled to the first terminal of the first resistor and a negative input terminal coupled to the second terminal of the first resistor; and

a third resistor having a first terminal coupled to an output terminal of the first operational amplifier and a second terminal outputting the adjustment signal.

5. The power supply apparatus according to claim 4, wherein the over voltage detecting unit comprises:

a Zener diode having a cathode coupled to the cathode of the isolation diode;

a fourth resistor having a first terminal coupled to an anode of the Zener diode;

a bipolar junction transistor (BJT) having a base coupled to a second terminal of the fourth resistor and the second terminal of the third resistor and an emitter coupled to a ground potential; and

a fifth resistor having a first terminal coupled to the second terminal of the second resistor and a second terminal coupled to a collector of the BJT.

6. The power supply apparatus according to claim 5, wherein the BJT is an NPN type BJT.

7. The power supply apparatus according to claim 4, wherein the over voltage detecting unit comprises:

a Zener diode having a cathode coupled to the cathode of the isolation diode;

a fourth resistor having a first terminal coupled to an anode of the Zener diode;

a second operational amplifier having a positive input terminal receiving a reference voltage and a negative input terminal coupled to the second terminal of the third resistor and a second terminal of the fourth resistor;

a fifth resistor having a first terminal coupled to the second terminal of the second resistor;

a diode having an anode coupled to a second terminal of the fifth resistor and a cathode coupled to an output terminal of the second operational amplifier; and

a sixth resistor having a first terminal coupled to the negative terminal of the second operational amplifier and a second terminal coupled to the output terminal of the second operational amplifier.

8. The power supply apparatus according to claim 1, wherein the main power generating unit comprises:

a switch having a first terminal receiving the DC input voltage and a control terminal receiving the control signal;

a diode having an anode coupled to a ground potential and a cathode coupled to a second terminal of the switch;

an inductor having a first terminal coupled to the second terminal of the switch and a second terminal coupled to the first terminal of the first resistor for generating the main power; and

a capacitor having a first terminal coupled to the second terminal of the inductor and a second terminal coupled to the ground potential.

9. The power supply apparatus according to claim 8, wherein the main power generating unit is a DC-to-DC converter.

10. The power supply apparatus according to claim 8, wherein the DC-to-DC converter comprises an isolation type boost converter and/or buck converter, or a non-isolation type boost converter and/or buck converter.