CONTROL VOLTAGE ADJUSTING CIRCUIT, FEEDBACK SIGNAL GENERATING CIRCUIT, AND CONTROL CIRCUIT INCLUDING THE SAME

• US 20160056725A1
• Filed: 02/09/2015
• Published: 02/25/2016
• Est. Priority Date: 08/21/2014
• Status: Active Grant

• Current Assignee: Solum Co., Ltd.
• Original Assignee: Samsung Electro-Mechanics Co., Ltd. (Samsung Group)
• Inventors: Kim, Ki Hong, Ryu, Byoung Woo, Choi, Jung Woo
• Granted Patent: US 9,614,450 B2
• Time in Patent Office: Days
• US Class Current: 1/1
• CPC Class Codes: H02M 1/0025 Arrangements for modifying reference values, feedback values or error values in the control loop of a converter
• CPC Class Codes: H02M 1/0058 by employing soft switching techniques, i.e. commutation of transistors when applied voltage is zero or when current flow is zero using an auxiliary actively switched resonant commutation circuit connected to an intermediate DC voltage or between two push-pull branches of an inverter bridge H02M7/4811; in resonant inverters H02M7/4815; in inverters operating from a resonant DC source H02M7/4826
• CPC Class Codes: H02M 3/33538 of the forward type H02M3/3353, H02M3/33569 take precedence
• CPC Class Codes: H02M 3/3376 with automatic control of output voltage or current
• CPC Class Codes: H05B 45/10 Controlling the intensity of the light
• CPC Class Codes: H05B 45/3725 Switched mode power supply [SMPS]
• CPC Class Codes: H05B 45/382 with galvanic isolation between input and output
• CPC Class Codes: H05B 45/39 Circuits containing inverter bridges
• CPC Class Codes: Y02B 70/10 Technologies improving the efficiency by using switched-mode power supplies [SMPS], i.e. efficient power electronics conversion e.g. power factor correction or reduction of losses in power supplies or efficient standby modes

Abstract

A feedback signal generating circuit may include a control voltage adjusting circuit outputting a feedback voltage by comparing a control voltage input from an external voltage source with a reference voltage and adjusting a ratio of control voltage drop, and an amplifying circuit generating a feedback signal by differentially amplifying the feedback voltage and a detection voltage associated with a current flowing in a load.

Claims

1. A control voltage adjusting circuit, comprising:

a comparing unit comparing a control voltage input from an external voltage source with a reference voltage; and

a voltage dividing unit adjusting a ratio of control voltage drop depending on a comparison result of the comparing unit.

2. The control voltage adjusting circuit of claim 1, wherein the voltage dividing unit includes a first resistor and a second resistor which are connected in series between a node to which the control voltage is input and a ground, and a third resistor having one end connected between the first resistor and the second resistor and an other end connected to an output terminal of the comparing unit.

3. The control voltage adjusting circuit of claim 2, wherein the comparing unit floats the other end of the third resistor or short-circuits the other end of the third resistor to the ground, depending on the comparison result.

4. The control voltage adjusting circuit of claim 3, wherein the comparing unit floats the other end of the third resistor when the control voltage is higher than the reference voltage, and short-circuits the other end of the third resistor to the ground when the control voltage is lower than the reference voltage.

5. The control voltage adjusting circuit of claim 2, wherein the comparing unit includes:

a first operational amplifier having a non-inverting terminal to which the control voltage is applied and an inverting terminal to which the reference voltage is applied; and

a transistor disposed between the other end of the third resistor and the ground to perform a switching operation in response to an output signal of the first operational amplifier.

6. The control voltage adjusting circuit of claim 5, wherein the transistor includes a p-type field effect transistor including a source connected to the other end of the third resistor, a drain connected to the ground, and a gate connected to an output terminal of the first operational amplifier.

7. A feedback signal generating circuit, comprising:

a control voltage adjusting circuit outputting a feedback voltage by comparing a control voltage input from an external voltage source with a reference voltage and adjusting a ratio of control voltage drop; and

an amplifying circuit generating a feedback signal by differentially amplifying the feedback voltage and a detection voltage associated with a current flowing in a load.

8. The feedback signal generating circuit of claim 7, wherein the control voltage adjusting circuit includes:

a comparing unit comparing the control voltage with the reference voltage; and

a voltage dividing unit generating the feedback voltage by adjusting the ratio of the control voltage drop depending on a comparison result of the comparing unit.

9. The feedback signal generating circuit of claim 8, wherein the voltage dividing unit includes a first resistor and a second resistor connected in series between a node to which the control voltage is input and a ground, and a third resistor having one end connected to a connection node between the first resistor and the second resistor and an other end connected to an output terminal of the comparing unit, and

the feedback voltage is generated at the connection node between the first resistor and the second resistor.

10. The feedback signal generating circuit of claim 9, wherein the comparing unit floats the other end of the third resistor or short-circuits the other end of the third resistor to the ground, depending on the comparison result.

11. The feedback signal generating circuit of claim 9, wherein the comparing unit floats the other end of the third resistor when the control voltage is higher than the reference voltage, and short-circuits the other end of the third resistor to the ground when the control voltage is lower than the reference voltage.

12. The feedback signal generating circuit of claim 9, wherein the comparing unit includes:

a first operational amplifier having a non-inverting terminal to which the control voltage is applied and an inverting terminal to which the reference voltage is applied; and

a transistor connected between the other end of the third resistor and the ground to perform a switching operation in response to an output signal of the first operational amplifier.

13. The feedback signal generating circuit of claim 12, wherein the transistor includes a p-type field effect transistor including a source connected to the other end of the third resistor, a drain connected to the ground, and a gate connected to an output terminal of the first operational amplifier.

14. The feedback signal generating circuit of claim 7, wherein the amplifying circuit includes:

an inverting terminal to which the detection voltage is applied;

a non-inverting terminal to which the feedback voltage is applied; and

an output terminal from which the feedback signal is output, the feedback signal being negative-feedback to the inverting terminal.

15. A control circuit of a power converting circuit supplying an output voltage to a load connected to a secondary side, electrically insulated from a primary side, by switching an input voltage input to the primary side, the control circuit comprising:

a feedback signal generating circuit generating a feedback voltage by adjusting a ratio of control voltage drop depending on the control voltage input from an external voltage source and a reference voltage, and generating a feedback signal by differentially amplifying the feedback voltage and a detection voltage associated with a current flowing in the load; and

a switching signal generating circuit controlling a switching operation of the input voltage depending on the feedback signal.

16. The control circuit of claim 15, further comprising a feedback circuit transferring the feedback signal to the switching signal generating circuit.