Control circuit and electronic device

• US 8,698,547 B2
• Filed: 09/21/2012
• Issued: 04/15/2014
• Est. Priority Date: 11/18/2011
• Status: Active Grant

• Current Assignee: Fujitsu Limited
• Original Assignee: Fujitsu Limited
• Inventors: Nakao, Hiroshi
• Primary Examiner(s): Nguyen, Long
• Assistant Examiner(s): CHEN, PATRICK C
• Application Number:
  US13/624,122
• Publication Number:
  US 20130127518A1
• Time in Patent Office: 571 Days
• Field of Search: 327/434
• US Class Current: 327/434
• CPC Class Codes: H01L 29/2003 Nitride compounds
• CPC Class Codes: H01L 29/7787 with wide bandgap charge-carrier supplying layer, e.g. direct single heterostructure MODFET
• CPC Class Codes: H02M 1/36 Means for starting or stopping converters
• CPC Class Codes: H03K 17/0412 by measures taken in the control circuit
• CPC Class Codes: H03K 17/06 Modifications for ensuring a fully conducting state
• 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 control circuit includes: a first switching element having a source, a gate, and a drain; a battery configured to supply a voltage to the gate through a second switching element; a PWM signal generator circuit configured to supply a PWM signal to the gate through a third switching element; and a gate control circuit configured to, under a power-off condition, turn on the second switching element to supply the voltage of the battery to the gate and turns off the third switching element, and configured to under a power-on condition, turn on the third switching element to supply the PWM signal voltage to the gate and turns off the second switching element.

Claims

1. A control circuit comprising:

a first switching element having a source, a gate, and a drain;

a second switching element configured to supply positive voltage of a battery to the gate under a power-off condition of the control circuit; and

a third switching element configured to supply a pulse width modulation signal of a signal generator to the gate of under a power-on condition of the control circuit, the pulse width modulation signal is not supplied to the gate under the power-off condition of the control circuit.

2. The control circuit according to claim 1,

wherein the first switching element is a GaN-HEMT rendered normally-off from a normally-off state.

3. The control circuit according to claim 2,

wherein the voltage of the battery is higher than a threshold voltage of the GaN-HEMT rendered normally-off.

4. The control circuit according to claim 1,

wherein a signal generator circuit outputs a first PWM signal having a first frequency, and a second PWM signal having a second frequency that is lower than the first frequency.

5. The control circuit according to claim 1,

wherein the second switching element is a PMOS-FET, and the third switching element is an NMOS-FET.

6. The control circuit according to claim 1, further comprising:

an inrush current blocking circuit on the drain side of the first switching element,

wherein the inrush current blocking circuit includes a triac and a resistor connected in series, and a relay connected in parallel with the triac and the resistor.

7. An electronic device comprising:

a converter circuit including;

a first switching element having a source, a gate, and a drain;

a second switching element configured to supply positive voltage of a battery to the gate under a power-off condition of the control circuit; and

a third switching element configured to supply a pulse width modulation signal of a signal generator to the gate of under a power-on condition of the control circuit, the pulse width modulation signal is not supplied to the gate under the power-off condition of the control circuit.