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Patent Searching and Data


Title:
SWITCHING POWER SUPPLY CIRCUIT
Document Type and Number:
Japanese Patent JP2009038928
Kind Code:
A
Abstract:

To provide an inexpensive boot-strap type switching power supply circuit which stably performs power feeding to a circuit for driving a switching element even at light loading.

The switching power supply circuit comprises: the switching element 1; a boot strap circuit having a boot-strapping capacitor C1 connected to a source of the switching element 1 at its one end; the drive circuit 4 which generates a drive signal fed to a gate of the switching element by using a boot strap voltage VB outputted from the boot strap circuit; a voltage controlling DMOS 5 arranged between the source of the switching element 1 and the ground; and a current limit part (including a voltage detecting DMOS 6, a voltage detecting NMOS 7, a voltage detecting resistor 8, a comparator 11, and a DMOS driver 9) for limiting a current flowing in the voltage controlling DMOS 5.


Inventors:
KANAMORI ATSUSHI
IKUTA YOSHINORI
Application Number:
JP2007202469A
Publication Date:
February 19, 2009
Filing Date:
August 03, 2007
Export Citation:
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Assignee:
SHARP KK
International Classes:
H02M1/08; H02M3/155
Domestic Patent References:
JP2007068269A2007-03-15
JP2002281744A2002-09-27
JP2005304210A2005-10-27
Attorney, Agent or Firm:
Shizuo Sano
Inoue On
Kazutoshi Shibuya