CS8101 datasheet(4/8 Pages) CHERRY

4 / 8 page

Figure 3. RC Network for

Delay

An external RC network on the

lead (Figure 3) pro-

vides a sufficiently long delay for most microprocessor

based applications. RC values can be chosen using the

following formula:

ÐtDelay

RTOTCRST =

[ln

]

where:

RRST =

Delay resistor

RIN

= µP port impedance

RTOT = RRST in parallel with RIN

CRST =

Delay capacitor

tDelay = desired delay time

VRST = VSAT of

lead (0.7V @ turn - ON)

threshold

RESET

)

VT Ð VOUT

VRST Ð VOUT

(

RESET

CS8101

VOUT

CRST

RRST

COUT

5V to

and

System

Power

RESET

Port

The circuit depicted in Figure 4 lets the microprocessor

control its power source, the CS8101 regulator. An I/O

port on the µP and the SWITCH port are used to drive the

base of Q1. When Q1 is driven into saturation, the voltage

on the

lead falls below its lower threshold. The

regulatorÕs output is enabled. When the drive current is

removed, the voltage on the

lead rises, the out-

put is switched off and the IC moves into Sleep mode

where it draws 50µA (max).

By coupling these two controls with the

lead, the

system has added flexibility. Once the system is running,

the state of the SWITCH is irrelevant as long as the I/O

port continues to drive Q1. The microprocessor can turn

off its own power by withdrawing drive current, once the

SWITCH is open. This software control at the I/O port

allows the microprocessor to finish key housekeeping

functions before power is removed.

The logic options are summarized in Table 1.

ENABLE

Applications Notes

Circuit Description: continued

0.1

VIN

Gnd

CS8101

VOUT

500k

100k

CRST

RRST

COUT

VCC

I/O Port

SWITCH

VBAT

RESET

ENABLE

RESET

Figure 4. Microprocessor Control of CS8101 using external switching transistor Q1.

CS8101 датащи(PDF) 4 Page - Cherry Semiconductor Corporation

CS8101 датащи(HTML) 4 Page - Cherry Semiconductor Corporation

Html Pages

1 2 3 4 5 6 7 8

датащи скачать

ссылки URL