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EFFICIENCY IMPROVEMENT FOR BATTERY SAVER SLEEP MODE

IP.com Disclosure Number: IPCOM000006318D
Original Publication Date: 1991-Dec-01
Included in the Prior Art Database: 2001-Dec-24
Document File: 1 page(s) / 64K

Publishing Venue

Motorola

Related People

Bob Stengel: AUTHOR

Abstract

During inactive receiver standby mode selective cir- cuits are placed in a sleep or off mode (much lower or zero current drain), to conserve battery extending the operation time. A preferred method of reducing or eliminating a circuits battery drain is to open the current drain path without discharging supply lime bypass capacitors. The energy used to initially charge the supply bypass is Ec = ;CV* Joules Where: C = capacitance in Farads V = the voltage across the capacitor electrodes This can be accomplished with a series switching transistor or removal of transistor biasing. When a series switch cannot be provided, the circuit current is reduced by disconnecting the supply. Figure 1, is an example using supply switching as a means of putting the circuits in a sleep mode. The regulator function is switched off and the charge on Cl is discharge through the circuit to ground.

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MOTOROLA ;NC. Technical Developments Volume 14 December 1991

EFFICIENCY IMPROVEMENT FOR BATTERY SAVER SLEEP MODE

by Bob Stengel

   During inactive receiver standby mode selective cir- cuits are placed in a sleep or off mode (much lower or zero current drain), to conserve battery extending the operation time. A preferred method of reducing or eliminating a circuits battery drain is to open the current drain path without discharging supply lime bypass capacitors. The energy used to initially charge the supply bypass is

Ec = ;CV* Joules

Where: C = capacitance in Farads

V = the voltage across the capacitor electrodes

  This can be accomplished with a series switching transistor or removal of transistor biasing. When a series switch cannot be provided, the circuit current is reduced by disconnecting the supply. Figure 1, is an example using supply switching as a means of putting the circuits in a sleep mode. The regulator function is switched off and the charge on Cl is discharge through the circuit to ground.

circuit turn-on (t,J or warm-up time, peak current lev- els (I& during charging,,and the power consumed (P, watts or I, amperes) charging the capacitor at the sleep switching rate (F,). For Cl = 100 uF Cl ESR = 5 Ohms, V,, = S.OV, F, = 10 Hz (100 mSec sleep mode cycles), and Rl = 100 Ohms (Il= 5 mA), the above parameters are:

torr = RlXCl = LO msec. for v, = c-1 x v,, = 1.83 "O,t$

tan = ESRXCL

= 05 msec. fcx ", = t I -c-1 ) x VO", = 3.16 volt?

I,., = ",,,ImR~ = L...