Controller for controlling blocking switch of power converter

Abstract

A controller for controlling a blocking switch of a power converter is provided. The controller includes a control pin and a sensing circuit. The control pin is coupled to the control end of the blocking switch and the output end of the blocking switch. The sensing circuit comprises a control switch and a judgment circuit. The first end of the control switch is coupled to the control pin. The second end of the control switch is coupled to a reference low voltage. The determination circuit turns on the control switch to obtain a sensed current value of a current flowing through the control switch when the blocking switch is turned off. When the sensed current value is lower than the reference current value, the determination circuit provides a notification signal for allowing the blocking switch to be turned on.

Description

Technical Field

[0001] The invention relates to a controller, and in particular to a controller for controlling a blocking switch of a power converter. Background Art

[0002] Generally speaking, the power converter can output the output power provided by the power converter through a blocking switch. Based on the Vsafe0V specification, the blocking switch is allowed to be turned on only when the voltage value at the output end of the blocking switch is lower than a specified value (e.g., 0 to 0.8 volts). Therefore, the controller for controlling the blocking switch must have a control pin for controlling the blocking switch and a detection pin for detecting the voltage value at the output end (e.g., Vbus end) of the blocking switch.

[0003] Based on the trend of reducing the size of components, the number of pins of the controller is reduced. Therefore, how to use the same pins to detect the voltage value at the output end of the blocking switch and perform a switching operation on the blocking switch is one of the research focuses of those skilled in the art. Summary of the invention

[0004] The present invention provides a controller for controlling a blocking switch of a power converter, which can utilize a single pin to detect a voltage value at an output end of the blocking switch and perform a switching operation on the blocking switch.

[0005] The controller of the present invention is used to control the blocking switch of the power converter. The controller includes a control pin and a sensing circuit. The control pin is coupled to the control end of the blocking switch and the output end of the blocking switch. The controller controls the switching operation of the blocking switch through the control pin. The sensing circuit includes a control switch and a judgment circuit. The first end of the control switch is coupled to the control pin. The second end of the control switch is coupled to a reference low voltage. The judgment circuit is coupled to the first end of the control switch and the control pin. The judgment circuit turns on the control switch during the period when the blocking switch is turned off to obtain a sensed current value of the current flowing through the control switch. When the sensed current value is lower than the reference current value, the judgment circuit provides a notification signal for allowing the blocking switch to be turned on.

[0006] Based on the above, the control pin is coupled to the control end of the blocking switch and the output end of the blocking switch. The controller controls the switching operation of the blocking switch through the control pin. The judgment circuit obtains the sensed current value through the control pin and decides whether to provide a notification signal accordingly. The controller of the present invention can control the switching operation of the blocking switch through the control pin and detect the voltage value at the output end of the blocking switch. In this way, the number of pins of the controller can be reduced. In addition, the size of the controller can also be reduced. BRIEF DESCRIPTION OF THE DRAWINGS

[0007] Figure 1 is a schematic diagram of a blocking switch and a controller according to an embodiment of the present invention;

[0008] Figure 2 is a schematic diagram of a blocking switch and a controller according to an embodiment of the present invention;

[0009] Figure 3 It is a schematic diagram of a blocking switch and a controller according to an embodiment of the present invention.

[0010] Description of Reference Numerals

[0011] 100, 200, 220': Controller

[0012] 110, 210: Control pins

[0013] 120, 220, 220': Sensing circuit

[0014] 121, 221: Judgment circuit

[0015] 2211: Current Sensor

[0016] 2212: Comparator

[0017] D1: diode

[0018] ERC: Resistor Circuit

[0019] IG: Current flowing through the control switch

[0020] IREF: reference current value

[0021] ISEN: sensing current value

[0022] R1, R2: Resistors

[0023] REQ: Equivalent resistance value

[0024] SC, SD: control signal

[0025] SN: Notification Signal

[0026] SWB: Block switch

[0027] SWC: Switch Control

[0028] TC: Control terminal of blocking switch

[0029] TI: input terminal of blocking switch

[0030] TO: Output terminal of blocking switch

[0031] VCC: output power supply

[0032] VDC: Voltage source

[0033] VSS: Reference low voltage DETAILED DESCRIPTION

[0034] Some embodiments of the present invention will be described in detail below in conjunction with the accompanying drawings. The referenced element symbols in the following description will be regarded as the same or similar elements when the same element symbols appear in different drawings. These embodiments are only part of the present invention and do not disclose all possible implementation methods of the present invention. More specifically, these embodiments are only examples in the claims of the present invention.

[0035] Please refer to Figure 1 , Figure 1 It is a schematic diagram of a blocking switch and a controller according to an embodiment of the present invention. Figure 1 The blocking switch SWB of the power converter and the controller 100 for controlling the blocking switch SWB are shown. In this embodiment, the controller 100 includes a control pin 110 and a sensing circuit 120. The control pin 110 is coupled to the control terminal TC of the blocking switch SWB and the output terminal TO of the blocking switch SWB. The controller 100 controls the switching operation of the blocking switch SWB through the control pin 110.

[0036] For example, the blocking switch SWB can be implemented by an N-type field effect transistor. The blocking switch SWB is, for example, an NMOS field effect transistor. The input terminal TI of the blocking switch SWB receives the output power VCC. The controller 100 provides a control signal SD having a high voltage level to the control terminal TC of the blocking switch SWB through the control pin 110, thereby turning on the blocking switch SWB. Therefore, the blocking switch SWB transmits the output power VCC to the output terminal. The controller 100 provides a control signal SD having a low voltage level to the control terminal TC of the blocking switch SWB through the control pin 110, thereby turning off the blocking switch SWB. Therefore, the blocking switch SWB does not transmit the output power VCC to the output terminal.

[0037] In the present embodiment, the sensing circuit 120 includes a control switch SWC and a judgment circuit 121. A first end of the control switch SWC is coupled to the control pin 110. A second end of the control switch SWC is coupled to a reference low voltage VSS. The judgment circuit 121 is coupled to the first end of the control switch SWC and the control pin 110. The judgment circuit 121 turns on the control switch SWC during the period when the blocking switch SWB is turned off to obtain a sensed current value ISEN of the current IG flowing through the control switch SWC. When the sensed current value ISEN is lower than the reference current value IREF, the judgment circuit 121 provides a notification signal SN for allowing the blocking switch SWB to be turned on. The controller 100 responds to the notification signal SN to turn off the control switch SWC and turn on the blocking switch SWB through the control pin 110.

[0038] It is worth mentioning that the controller 100 controls the switching operation of the blocking switch SWB through the control pin 110. The judgment circuit 121 obtains the sensed current value ISEN through the control pin 110 and determines whether to provide the notification signal SN accordingly. The controller 100 of the present invention can control the switching operation of the blocking switch SWB through the control pin 110 and detect the voltage value at the output terminal TO of the blocking switch SWB. In this way, the number of pins of the controller 100 can be reduced. In addition, the size of the controller 100 can also be reduced.

[0039] Specifically, when the sensed current value ISEN is lower than the reference current value IREF, the determination circuit 121 learns that the voltage value at the output terminal TO of the blocking switch SWB is lower than the standard voltage value at which the blocking switch SWB is allowed to be turned on. This indicates that the blocking switch SWB can meet the standard of Vsafe0V and is allowed to be turned on. Therefore, the determination circuit 121 provides the notification signal SN.

[0040] In this embodiment, when the sensed current value ISEN is higher than or equal to the reference current value IREF, the determination circuit 121 does not provide the notification signal SN. Therefore, the controller 100 continues to turn off the blocking switch SWB and continues to turn on the control switch SWC. In this embodiment, while the control switch SWC is turned on, the controller 100 uses the reference low voltage VSS to pull down the voltage value at the control pin 110. Therefore, the blocking switch SWB is continuously turned off.

[0041] In this embodiment, the control pin 110 is coupled to the output terminal TO of the blocking switch SWB via the resistor circuit ERC. The sensing current value ISEN is determined by the voltage value at the output terminal TO of the blocking switch SWB, the equivalent resistance value REQ of the resistor circuit ERC and the reference low voltage VSS.

[0042] In this embodiment, the control switch SWC can be implemented by a transistor switch. Taking this embodiment as an example, the control switch SWC can be an NMOS field effect transistor. The control end of the control switch SWC receives the control signal SC and is turned on or off in response to the control signal SC.

[0043] Please refer to Figure 2 , Figure 2 2 is a schematic diagram of a blocking switch and a controller according to an embodiment of the present invention. In this embodiment, the controller 200 includes a control pin 210 and a sensing circuit 220. The control pin 210 is coupled to the control terminal TC of the blocking switch SWB and the output terminal TO of the blocking switch SWB. The controller 200 controls the switching operation of the blocking switch SWB through the control pin 210. The sensing circuit 220 includes a control switch SWC and a judgment circuit 221. The first end of the control switch SWC is coupled to the control pin 210. The second end of the control switch SWC is coupled to a reference low voltage. In this embodiment, the reference low voltage is a ground terminal.

[0044] During the period when the blocking switch SWB is turned off, the judgment circuit 221 turns on the control switch SWC. The judgment circuit 221 includes a current sensor 2211 and a comparator 2212. The current sensor 2211 is coupled to the first end of the control switch SWC. The current sensor 2211 senses the current IG flowing through the control switch SWC during the period when the blocking switch SWB is turned off to generate a sensed current value ISEN. The comparator 2212 is coupled to the current sensor 2211. The comparator 2212 compares the sensed current value ISEN with the reference current value IREF during the period when the blocking switch SWB is turned off. When the sensed current value ISEN is lower than the reference current value IREF, the comparator 2212 provides a notification signal SN.

[0045] In this embodiment, the inverting input terminal of the comparator 2212 receives the sensing current value ISEN. The non-inverting input terminal of the comparator 2212 receives the reference current value IREF. Therefore, the notification signal SN output by the comparator 2212 is a signal with a high voltage level. The controller 100 responds to the notification signal SN to turn off the control switch SWC and turn on the blocking switch SWB through the control pin 110.

[0046] In the present embodiment, the control pin 210 is coupled to the output terminal TO of the blocking switch SWB via the resistance circuit ERC. The resistance circuit ERC includes resistors R1, R2 and a diode D1. The resistor R1 is coupled between the output terminal TO of the blocking switch SWB and the control pin 110. The first end of the resistor R2 is coupled to the output terminal TO of the blocking switch SWB. The second end of the resistor R2 is coupled to the anode of the diode D1. The cathode of the diode D1 is coupled to the control pin 110.

[0047] For example, it is assumed that the blocking switch SWB is allowed to be turned on only when the voltage value at the output terminal TO of the blocking switch SWB must be lower than 0.1 volt. In other words, the blocking switch SWB is allowed to be turned on only when the voltage difference between the output terminal TO of the blocking switch SWB and the ground terminal is lower than 0.1 volt. Therefore, the reference current value IREF is equal to the quotient value generated by dividing 0.1 volt by the equivalent resistance value REQ of the resistance circuit ERC. When the sensing current value ISEN is lower than the reference current value IREF, this means that the voltage value at the output terminal TO of the blocking switch SWB is lower than 0.1 volt. Therefore, the comparator 2212 provides the notification signal SN. On the other hand, when the sensing current value ISEN is higher than or equal to the reference current value IREF, the comparator 2212 does not provide the notification signal SN.

[0048] Please refer to Figure 3 , Figure 3 2 is a schematic diagram of a blocking switch and a controller according to an embodiment of the present invention. In this embodiment, the controller 200' includes a control pin 210 and a sensing circuit 220'. The control pin 210 is coupled to the control terminal TC of the blocking switch SWB and the output terminal TO of the blocking switch SWB. The controller 200' controls the switching operation of the blocking switch SWB through the control pin 210. The sensing circuit 220' includes a control switch SWC and a judgment circuit 221. The configuration of the judgment circuit 221 and the resistance circuit ERC have been Figure 2 The first terminal of the control switch SWC is coupled to the control pin 210. The second terminal of the control switch SWC is coupled to the reference low voltage VSS. Figure 2 The difference is that the reference low voltage VSS in this embodiment is provided by the voltage source VDC.

[0049] For example, the blocking switch SWB is allowed to be turned on only when the voltage value at the output terminal TO of the blocking switch SWB must be lower than 0.1 volt. The voltage source VDC provides a reference low voltage VSS having 0.1 volt. In other words, the blocking switch SWB is allowed to be turned on only when the voltage difference between the output terminal TO of the blocking switch SWB and the reference low voltage VSS is lower than 0 volt. Therefore, the reference current value IREF is equal to 0 ampere. When the sensed current value ISEN is lower than the reference current value IREF (i.e., the sensed current value ISEN is lower than 0 ampere), this indicates that the voltage value at the output terminal TO of the blocking switch SWB is lower than 0.1 volt. Therefore, the comparator 2212 provides the notification signal SN. On the other hand, when the sensed current value ISEN is higher than or equal to the reference current value IREF (i.e., the sensed current value ISEN is higher than or equal to 0 ampere), the comparator 2212 does not provide the notification signal SN.

[0050] In summary, the controller includes a control pin and a sensing circuit. The control pin is coupled to the control end of the blocking switch and the output end of the blocking switch. The controller controls the switching operation of the blocking switch through the control pin. The judgment circuit obtains the sensing current value through the control pin and determines whether to provide a notification signal accordingly. The controller can control the switching operation of the blocking switch through the control pin and detect the voltage value at the output end of the blocking switch. In this way, the number of pins of the controller can be reduced. In addition, the size of the controller can also be reduced.

[0051] Although the present invention has been disclosed as above by way of embodiments, it is not intended to limit the present invention. Any person skilled in the art may make some changes and modifications without departing from the spirit and scope of the present invention. Therefore, the protection scope of the present invention shall be determined by the scope of the appended claims.

Claims

1. A controller for controlling a blocking switch of a power converter, characterized in that: The controller comprises: a control pin coupled to the control end of the blocking switch and the output end of the blocking switch, wherein the controller controls the switching operation of the blocking switch through the control pin; and Sensing circuit, including: a control switch, wherein a first end of the control switch is coupled to the control pin, and a second end of the control switch is coupled to a reference low voltage; and The judgment circuit is coupled to the first end of the control switch and the control pin, and is configured to turn on the control switch when the blocking switch is disconnected to obtain a sensed current value of the current flowing through the control switch, and when the sensed current value is lower than a reference current value, provide a notification signal for allowing the blocking switch to be turned on.

2. The controller according to claim 1, characterized in that: The controller turns off the control switch in response to the notification signal, and turns on the blocking switch through the control pin.

3. The controller according to claim 1, characterized in that: When the sensed current value is higher than or equal to the reference current value, the determination circuit does not provide the notification signal.

4. The controller according to claim 1, characterized in that: When the sensed current value is higher than or equal to the reference current value, the controller continuously turns off the blocking switch and continuously turns on the control switch.

5. The controller according to claim 1, characterized in that: When the sensed current value is lower than the reference current value, the judgment circuit learns that the voltage value at the output end of the blocking switch is lower than the standard voltage value at which the blocking switch is allowed to be turned on.

6. The controller according to claim 1, characterized in that: The reference low voltage is a ground terminal.

7. The controller according to claim 1, characterized in that: The reference low voltage is provided by a voltage source.

8. The controller according to claim 1, characterized in that: The control pin is coupled to the output end of the blocking switch via a resistor circuit.

9. The controller according to claim 8, characterized in that: The sensing current value is determined by the voltage value at the output terminal of the blocking switch, the equivalent resistance value of the resistance circuit, and the reference low voltage.

10. The controller according to claim 1, characterized in that: The judgment circuit comprises: a current sensor coupled to the first end of the control switch and configured to sense the current flowing through the control switch during the period when the blocking switch is turned off to generate a sensed current value; and A comparator, coupled to the current sensor, is configured to compare the sensed current value with the reference current value during a period when the blocking switch is turned off, and provide the notification signal when the sensed current value is lower than the reference current value.

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