Power supply circuit using DC/DC converter

Patent metadata

Field	Value
Publication number	US-9819276-B2
Application number	US-201313955257-A
Country	US
Kind code	B2
Filing date	Jul 31, 2013
Priority date	Aug 9, 2012
Publication date	Nov 14, 2017
Grant date	Nov 14, 2017

Abstract

A power supply circuit comprises an input for receiving a power supply from a battery and a DC/DC converter for supplying a converted voltage to a load. A regulator is used for controlling the DC/DC converter such that the current drawn from the converter is smoothed. A charge storage device at the output of the DC/DC converter enables delivery of a non-constant current to the load.

First claim

The invention claimed is:

1. A power supply circuit, comprising:
an input for receiving a power supply from a battery;
a switched capacitor DC/DC converter for supplying a converted voltage to a load;
a regulator for controlling the switched capacitor DC/DC converter to reduce a ripple in the current drawn from the switched capacitor DC/DC converter; and
a charge storage device at an output of the switched capacitor DC/DC converter for delivering a non-constant current to the load, wherein the regulator comprises a controller configured to control an output resistance of the switched capacitor DC/DC converter by either adjusting a switching frequency or a capacitance of the switched capacitor DC/DC converter.

2. The power supply circuit as claimed in claim 1 , wherein the regulator ensures the ripple in the current drawn from the converter is less than 10% of an average current drawn.

3. The power supply circuit as claimed in claim 1 , wherein the charge storage device comprises:
an output capacitor connected between the output of the switched capacitor DC/DC converter and a reference line.

4. The power supply circuit as claimed in any preceding claim, wherein the regulator comprises a current mirror circuit at the output of the switched capacitor DC/DC converter which is fed by a current source.

5. An electronic device comprising:
the battery;
the power supply circuit as claimed in claim 1 ;
a first circuit powered by the switched capacitor DC/DC converter; and
a second circuit powered directly by the battery.

6. The device as claimed in claim 5 , wherein the first circuit comprises a digital integrated circuit and the second circuit comprises an analog circuit.

7. The device as claimed in claim 6 comprising a hearing aid, wherein the digital integrated circuit comprises a transceiver circuit.

8. The device as claimed in claim 7 , comprising the hearing aid, wherein the analog circuit comprises a loudspeaker and microphone drive circuit.

9. A power supply method, comprising:
receiving a power supply from a battery;
using a switched capacitor DC/DC converter to supply a converted voltage to a load;
controlling the switched capacitor DC/DC converter to reduce a ripple in a current drawn from the switched capacitor DC/DC converter; and
using a charge storage device at the output of the switched capacitor DC/DC converter to deliver a non-constant current to the load; and
controlling an output resistance of the switched capacitor DC/DC converter by either adjusting a switching frequency or a capacitance of the switched capacitor DC/DC converter.

10. The method as claimed in claim 9 , wherein the controlling further comprises:
fixing the current drawn from the switched capacitor DC/DC converter using a current source.

11. The method as claimed in claim 9 , further comprising:
adjusting the switching frequency to adjust the output resistance of the switched capacitor DC/DC converter.

12. The method as claimed in claim 9 , further comprising:
adjusting the capacitance to adjust the output resistance of the switched capacitor DC/DC converter.

Assignees

• Nxp Bv

Inventors

• Kroekenstoel Dave
• Thoen Steven

Classifications

• H02M3/33569 Primary

  having several active switching elements (H02M3/3353 takes precedence) · CPC title

• H02M3/07

  using capacitors charged and discharged alternately by semiconductor devices with control electrode {, e.g. charge pumps} · CPC title

• H04B2215/069

  Reduction of switch mode power supply ripple · CPC title

• H02M3/156 Primary

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

• H04R25/00

  Electric hearing aids · CPC title