Systems and methods for over-temperature protection and over-voltage protection for power conversion systems

Patent metadata

Field	Value
Publication number	US-9397550-B2
Application number	US-201314075303-A
Country	US
Kind code	B2
Filing date	Nov 8, 2013
Priority date	Sep 26, 2013
Publication date	Jul 19, 2016
Grant date	Jul 19, 2016

Abstract

Systems and methods are provided for protecting a power conversion system. A system controller includes a first controller terminal and a second controller terminal. The first controller terminal is configured to provide a drive signal to close and open a switch to affect a first current flowing through a primary winding of a power conversion system. The second controller terminal is configured to receive first input signals during one or more first switching periods and receive second input signals during one or more second switching periods. The system controller is configured to determine whether a temperature associated with the power conversion system is larger than a predetermined temperature threshold, and in response to the temperature associated with the power conversion system being larger than the predetermined temperature threshold, generate the drive signal to cause the switch open and remain open to protect the power conversion system.

First claim

What is claimed is:

1. A system controller for protecting a power conversion system, the system controller comprising:
a first controller terminal configured to provide a drive signal to close and open a switch to affect a first current flowing through a primary winding of a power conversion system, the drive signal being associated with one or more switching periods including one or more first switching periods and one or more second switching periods;
a second controller terminal configured to receive one or more first input signals during the one or more first switching periods and receive one or more second input signals during the one or more second switching periods; and
an over-temperature-protection component configured to receive a first voltage signal associated with a first input current flowing through a first resistor during a third switching period of the one or more first switching periods and receive a second voltage signal associated with a second input current flowing through the first resistor during a fourth switching period of the one or more first switching periods, the first input current and the second input current being different in magnitude;
wherein the system controller is configured to:
process information associated with the one or more first input signals;
determine whether a temperature associated with the power conversion system is larger than a predetermined temperature threshold based on at least information associated with the one or more first input signals; and
in response to the temperature associated with the power conversion system being larger than the predetermined temperature threshold, generate the drive signal to cause the switch to open and remain open to protect the power conversion system;

wherein the system controller is further configured to:
process information associated with the one or more second input signals;
determine whether an output voltage associated with a secondary winding of the power conversion system is larger than a predetermined voltage threshold based on at least information associated with the one or more second input signals; and
in response to the output voltage associated with the secondary winding of the power conversion system being larger than the predetermined voltage threshold, generate the drive signal to cause the switch to open and remain open to protect the power conversion system;

wherein the over-temperature-protection component is further configured to, in response to a difference between the first voltage signal and the second voltage signal being larger than a first predetermined threshold in magnitude, output a protection signal to generate the drive signal to cause the switch to open and remain open to protect the power conversion system.

2. The system controller of claim 1 wherein the second controller terminal is further configured to receive the one or more first input signals during only a first part of the one or more first switching periods and receive the one or more second input signals during only a second part of the one or more second switching periods.

3. The system controller of claim 1 wherein the over-temperature-protection component is further configured to, in response to the difference between the first voltage signal and the second voltage signal being larger than the first predetermined threshold in magnitude, generate the protection signal to cause the switch to be opened without any modulation.

4. The system controller of claim 1 wherein the over-temperature-protection component is further configured to, in response to the difference between the first voltage signal and the second voltage signal being larger than the first predetermined threshold in magnitude, generate the protection signal to cause the switch to remain open for a first period of time larger in duration than one switching period of the one or more first switching periods.

5. The system controller of claim 1 is further configured to, in response to the output voltage associated with the secondary winding of the power conversion system being larger than the predetermined voltage threshold, generate the drive signal to cause the switch to be opened without any modulation.

6. The system controller of claim 1 is further configured to, in response to the output voltage associated with the secondary winding of the power conversion system being larger than the predetermined voltage threshold, generate the drive signal to cause the switch to remain open for a first period of time larger in duration than one switching period of the one or more second switching periods.

7. The system controller of claim 1 wherein:
the second controller terminal is coupled to a first resistor terminal of a second resistor, the second resistor further including a second resistor terminal;
the second controller terminal is coupled to a first diode terminal of one or more first diodes, the one or more first diodes further including a second diode terminal;
the second diode terminal is coupled to a third resistor terminal of the first resistor, the first resistor further including a fourth resistor terminal; and
the second resistor terminal is configured to receive an output signal associated with an auxiliary winding coupled to the secondary winding.

8. The system controller of claim 7 wherein the first resistor is a thermal resistor associated with a resistance changing with temperature.

9. The system controller of claim 8 wherein the resistance decreases with increasing temperature.

10. The system controller of claim 7 wherein:
the first diode terminal is an anode terminal; and
the second diode terminal is a cathode terminal.

11. The system controller of claim 1 , further comprising:
a third controller terminal configured to receive a supply voltage;
a fourth controller terminal configured to receive a bias voltage;
a fifth controller terminal configured to receive a current-sensing signal related to the first current flowing through the primary winding; and
a sixth controller terminal configured to receive a feedback signal related to the output voltage.

12. The system controller of claim 11 wherein the system controller includes no other terminals.

13. The system controller of claim 11 wherein the first controller terminal, the second controller terminal, the third controller terminal, the fourth controller terminal, the fifth controller terminal, and the sixth controller terminal are six different pins respectively.

14. A system controller for protecting a power conversion system, the system controller comprising:
a first controller terminal configured to provide a drive signal to close and open a switch to affect a first current flowing through a primary winding of a power conversion system, the drive signal being associated with one or more switching periods including one or more first switching periods and one or more second switching periods;
a second controller terminal configured to receive one or more first input signals during the one or more first switching periods and receive one or more second input signals during the one or more second switching periods;
an over-temperature-protection component configured to receive a first voltage signal associated with a first input current flowing through a thermal resistor during a third switching period and receive a second voltage signal associated with a second input current flowing through the thermal resistor during a fourth switching period, the first input current and the second input current being different in magnitude, the first voltage signal and the second voltage signal being related to the

Assignees

• On Bright Electronics Shanghai Co Ltd

Inventors

• Huang Xiaomin
• Lyu Huawei
• Luo Qiang
• Fang Lieyi

Classifications

• H02M1/32 Primary

  Means for protecting converters other than automatic disconnection · CPC title

• H02M3/33523

  with galvanic isolation between input and output of both the power stage and the feedback loop · CPC title

• H02H5/042

  using temperature dependent resistors · CPC title

• H02M3/33515

  with digital control · CPC title

• H02H7/1213 Primary

  for DC-DC converters · CPC title