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Triangular Power Path Control for Wireless Power

IP.com Disclosure Number: IPCOM000237883D
Publication Date: 2014-Jul-17
Document File: 3 page(s) / 254K

Publishing Venue

The IP.com Prior Art Database

Abstract

In a wireless power system, the input voltage can as high as up to 20V. An Ultra-High Voltage (UHV) therefore is needed as a power FET of internal LDO to tolerate such high voltage. On the other hand, the input voltage could be as low as 3V to provide for high charger efficiency needed when the battery voltage is low, which will severely degrade the output current capability of the internal LDO. To solve such problem, a kind of triangular power path for wireless power is proposed. It can make the chip operation voltage lower and obtain high efficiency when the input voltage coming from the wireless power is low.

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Triangular Power Path Control for Wireless Power

Abstract

In a wireless power system, the input voltage can as high as up to 20V.  An Ultra-High Voltage (UHV) therefore is needed as a power FET of internal LDO to tolerate such high voltage.  On the other hand, the input voltage could be as low as 3V to provide for high charger efficiency needed when the battery voltage is low, which will severely degrade the output current capability of the internal LDO.  To solve such problem, a kind of triangular power path for wireless power is proposed.  It can make the chip operation voltage lower and obtain high efficiency when the input voltage coming from the wireless power is low.

Introduction

 

Fig. 1 - structure of  power path management for wireless power applications

The left part is the wireless power receiver, which gets power from the wireless transmitter by inductive coupling then delivers the power to the power management control part - right part in Fig. 1.  This is a triangular structure of power path management.  It includes three paths.

1.      First path is from vrect à vout, which provides the power for external system or battery charging by an external power FET.

2.      Second path is from the vrectàldo5v, which provides the power for the on chip SOG and internal analog modules.

3.      The third path is from voutàldo5v, which provides power from vout to ldo5v when the load on ldo5v over the output capability of internal LDO.

4.      These three paths comprise a triangle structure for the power path management at wireless power application

       In wireless power system, the amount of power for receiver part can be controlled by communication between transmitter and receiver based on the Qi protocol.  The voltage on VREC will vary with different loads when the power rece...