Switching converter and associated discharge method

Patent metadata

Field	Value
Publication number	US-9590503-B2
Application number	US-201414489343-A
Country	US
Kind code	B2
Filing date	Sep 17, 2014
Priority date	Sep 17, 2014
Publication date	Mar 7, 2017
Grant date	Mar 7, 2017

Abstract

A switching converter has an input port for receiving an input voltage and an output port for providing an output voltage. The switching converter has a power stage, an energy stored circuit, a power conversion circuit and a control circuit. The power stage has an input terminal coupled to the input port and an output terminal coupled to the output port. The energy stored circuit is charged by the input voltage and provides a first bias voltage which maintains a predetermined time period after the input voltage is less than a predetermined voltage level. The power conversion circuit provides a second bias voltage. The control circuit provides a control signal to control the power stage and discharges the output voltage based on a discharge control signal, wherein the control circuit is powered by either the first bias voltage or the second bias voltage.

First claim

We claim:

1. A switching converter, comprising: an input port, configured to receive an input voltage; an output port, configured to provide an output voltage; a power stage, having an input terminal, an output terminal and a control terminal, wherein the input terminal is coupled to the input port, and the output terminal is coupled to the output port; an energy stored circuit, having an input terminal coupled to the input port to receive the input voltage and an output terminal configured to provide a first bias voltage, wherein the first bias voltage maintains a predetermined time period after the input voltage becomes less than a threshold signal; a power conversion circuit, having an input terminal and an output terminal, wherein the input terminal is coupled to the input port to receive the input voltage, and the output terminal is configured to provide a second bias voltage; and a control circuit, having a first input terminal, a second input terminal, a third input terminal, a fourth input terminal and an output terminal, wherein the first input terminal is coupled to the output port, the second input terminal is configured to receive a discharge control signal, the third input terminal is coupled to the output terminal of the energy stored circuit to receive the first bias voltage, and the fourth input terminal is coupled to the output terminal of the power conversion circuit to receive the second bias voltage, and the output terminal is coupled to the control terminal of the power stage to provide a control signal based on the output voltage and a reference signal, wherein the control circuit is powered by either the first bias voltage or the second bias voltage; and wherein the control circuit is configured to discharge the output voltage based on the discharge control signal, when the input voltage is less than the threshold signal, the output voltage is fully discharged to ground by the control circuit, wherein the control circuit further comprising: a discharge switch, having a control terminal, wherein the discharge switch is configured to discharge the output voltage based on the discharge control signal.

2. The switching converter of claim 1 , wherein the energy stored circuit further comprising:
a block device, having a first terminal coupled to the input port and a second terminal; and
an energy stored device, coupled to the second terminal of the block device and is configured to provide the first bias voltage, and wherein the energy device is charged by the input voltage; and wherein
the block device is configured to block a current path from the energy stored device to the input port.

3. The switching converter of claim 1 , wherein the energy stored circuit further comprising:
a diode, having an anode coupled to the input port and a cathode; and
a first capacitor, having a first terminal coupled to the cathode of the diode, and a voltage across the first capacitor is provided as the first bias voltage.

4. The switching converter of claim 1 , wherein the discharge control signal is provided based on comparing the input voltage with the threshold signal.

5. The switching converter of claim 1 , wherein the control circuit further comprising: a driving circuit, having an input terminal, a bias terminal and an output terminal, wherein the input terminal is configured to receive the discharge control signal, the bias terminal is coupled to the output terminal of the energy stored circuit to receive the first bias voltage, and the output terminal is configured to provide a drive signal to the control terminal of the discharge switch, and wherein the driving circuit is powered by the first bias voltage.

6. The switching converter of claim 1 , wherein the control circuit further comprising a reference generating circuit, configured to provide the reference signal based on the discharge control signal, wherein the reference signal ramps down when the discharge signal becomes effective, and wherein the reference generating circuit is powered by either the first bias voltage or the second bias voltage.

7. A switching converter, comprising: an input port, configured to receive an input voltage; an output port, configured to provide an output voltage; a comparison circuit, configured to provide a discharge control signal based on the input voltage and a threshold signal; a power stage, configured to provide the output voltage; an energy stored circuit, configured to provide a first bias voltage, wherein the first bias voltage maintains a predetermined time period after the input voltage is less than the threshold signal; and a control circuit, configured to provide a control signal to control the power stage based on the output voltage and a reference signal, and wherein the control circuit is configured to discharge the output voltage based on the discharge control signal; and wherein when the input voltage is less than the threshold signal, the output voltage is completely discharged by the control circuit; wherein the control circuit further comprising a reference generating circuit, the reference generating circuit comprises: a second capacitor, having a first terminal and a second terminal; a first current source, having a first terminal and a second terminal, wherein the first terminal is coupled to the first bias voltage or the second bias voltage, and wherein the second terminal is coupled to the first terminal of the second capacitor; and a second current source, having a first terminal and a second terminal, wherein the first terminal is coupled to the first terminal of the second capacitor, and wherein the second terminal is coupled to the second terminal of the second capacitor; and wherein the second capacitor is discharged by the second current source when the discharge control signal is effective.

8. The switching converter of claim 7 , wherein the energy stored circuit further comprising:
an energy stored device, wherein the energy stored device is charged by the input voltage, and the energy stored device is configured to supply the first bias voltage; and
a block device, coupled to the energy stored device in series for blocking a current path from the energy stored device to the input port.

9. The switching converter of claim 7 , wherein the control circuit further comprising:
a discharge switch, having a first terminal, a second terminal and a control terminal, wherein the first terminal is coupled to the output port, the second terminal is coupled to a system ground; and
a driving circuit, having an input terminal, a bias terminal and an output terminal, wherein the input terminal is configured to receive the discharge control signal, the bias terminal is configured to receive the first bias voltage, and the output terminal is coupled to the control terminal of the discharge switch to provide a driving signal, and wherein the driving circuit is powered by the first bias voltage.

10. The switching converter of claim 9 , wherein the energy stored circuit further comprising:
a diode, having an anode coupled to the input port and a cathode; and
a first capacitor, having a first terminal and a second terminal, wherein the first terminal is coupled to the cathode of the diode, and the second terminal is coupled to the system ground; and wherein
the first terminal of the first capacitor is coupled to the bias terminal of the driving circuit to provide the first bias voltage.

11. The switching converter of claim 7 , further comprising a power conversion circuit, having an input terminal and an output terminal, wherein the input terminal is coupled to the input port to receive the input voltage, and the output terminal is configured to provide a second bias voltage.

Assignees

• Monolithic Power Systems Inc

Inventors

• Lai Pengjie
• Jiang Jian

Classifications

• H02M3/158 Primary

  including plural semiconductor devices as final control devices for a single load · CPC title

• H02M1/36

  Means for starting or stopping converters · CPC title

• H02M3/156

  with automatic control of output voltage or current, e.g. switching regulators · CPC title

• H02M2001/322

  Electricity · mapped topic

• H02M1/322

  Means for rapidly discharging a capacitor of the converter for protecting electrical components or for preventing electrical shock · CPC title