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

Patent metadata

Field	Value
Publication number	US-9972994-B2
Application number	US-201615177258-A
Country	US
Kind code	B2
Filing date	Jun 8, 2016
Priority date	Sep 26, 2013
Publication date	May 15, 2018
Grant date	May 15, 2018

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 a first switching period, a second switching period, and a third switching period; and
a second controller terminal configured to receive a first input signal during the first switching period, receive a second input signal during the second switching period, and receive a third input signal during the third switching period;
wherein:
the first switching period includes a first start time and a first end time;
the second switching period includes a second start time and a second end time; and
the third switching period includes a third start time and a third end time;

wherein:
the first end time of the first switching period precedes the second start time of the second switching period; and
the second end time of the second switching period precedes the third start time of the third switching period;

wherein the system controller is configured to:
process information associated with the first input signal received during the first switching period and the third input signal received during the third switching period;
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 first input signal and the third input signal; 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 second input signal;
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 second input signal; 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 second controller terminal is further configured to:
receive the first input signal during only a first part of the first switching period;
receive the second input signal during only a second part of the second switching period; and
receive the third input signal during only a third part of the third switching period;

wherein:
the first part is smaller in magnitude than the first switching period, the first part starting at the first start time of the first switching period and ending before the first end time of the first switching period;
the second part is smaller in magnitude than the second switching period, the second part starting at the second start time of the second switching period and ending before the second end time of the second switching period; and
the third part is smaller in magnitude than the third switching period, the third part starting at the third start time of the third switching period and ending before the third end time of the third switching period.

2. 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 to, generate the drive signal to cause the switch to be opened without any modulation.

3. 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 to, generate the drive signal to cause the switch to remain open for a first period of time larger in duration than one of the second switching periods.

4. The system controller of claim 1 wherein:
the second controller terminal is coupled to a first resistor terminal of a first resistor, the first 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 a second resistor, the second 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.

5. The system controller of claim 4 wherein the second resistor is a thermal resistor associated with a resistance changing with temperature.

6. The system controller of claim 5 wherein the resistance decreases with increasing temperature.

7. The system controller of claim 4 wherein:
the first diode terminal is an anode terminal; and
the second diode terminal is a cathode terminal.

8. 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.

9. The system controller of claim 8 wherein the system controller includes no other terminals.

10. The system controller of claim 8 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.

11. A system for protecting a power conversion system, the system comprising:
a system controller including 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, and a second controller terminal configured to receive one or more input signals, the power conversion system further including a secondary winding and an auxiliary winding, the primary winding coupled to the secondary winding;
a first resistor including a first resistor terminal and a second resistor terminal, the first resistor terminal being directly coupled to the second controller terminal;
one or more first diodes including a first diode terminal and a second diode terminal, a first diode terminal being coupled to the second controller terminal; and
a second resistor including a third resistor terminal and a fourth resistor terminal, the third resistor terminal being coupled to the second diode terminal;
wherein the second resistor terminal is directly coupled to the auxiliary winding and is configured to receive an output signal associated with the auxiliary winding coupled to the secondary winding.

12. The system of claim 11 wherein the second resistor is a thermal resistor associated with a resistance changing with temperature.

13. The system of claim 12 wherein the resistance decreases with increasing temperature.

14. The system of claim 11 wherein:
the first diode terminal is an anode terminal; and
the second diode terminal is a cathode termin

Assignees

• On Bright Electronics Shanghai Co Ltd

Inventors

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

Classifications

• H02M1/32

  Means for protecting converters other than automatic disconnection · CPC title

• H02M3/33515

  with digital control · CPC title

• H02H5/042

  using temperature dependent resistors · CPC title

• H02H7/1213 Primary

  for DC-DC converters · CPC title

• H02H3/20

  responsive to excess voltage · CPC title