HT7039A-3 데이터 시트보기 (PDF) - Holtek Semiconductor

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HT7039A-3

TinyPowerTM Voltage Detector

Holtek Semiconductor 

HT70xxA-3

5V Power Line Monitoring Circuit

Generally, a minimum operating voltage of 4.5V

is guaranteed in a 5V power line system. The

HT7044A-3 is recommended for use as 5V power line

monitoring circuit.

• 5V power line monitor with power-on reset

5 V P o w e r lin e

R

D

C

V SS

V DD

V OUT

H T 7 0 4 4 A -3

V SS

• with 5V voltage regulator

5 V V o lta g e r e g u la to r

V IN

H T 7 1 5 0 -3 5 V

GND

V DD

V OUT

H T 7 0 4 4 A -3

V SS

Change of Detectable Voltage

If the required voltage is not found in the standard

product selection table, it is possible to change it by

using external resistance dividers or diodes.

• Varying the detectable voltage with a resistance

divider

V IN

RA

V DD

V OUT

H T 7 0 x x A -3

RB

V SS

V SS

Detectable voltage=(RA+RB)/RB×VDET

Hysteresis width=(RA+RB)/RB×VHYS

• Varying the detectable voltage with a diode

V IN

V f1

V f2

V DD

V OUT

H T 7 0 x x A -3

V SS

V SS

Detectable voltage=Vf1+Vf2+VDET

Malfunction Analysis

The following circuit demonstrates the way a circuit analyzes

malfunctions by monitoring the variation or spike noise of power

supply voltage.

V DD

V OUT

H T 7 0 x x A -3

V SS

V SS

Charge Monitoring Circuit

The following circuit shows a charged monitor

for protection against battery deterioration by

overcharging. When the voltage of the battery is

higher than the set detectable voltage, the transistor

turns on to bypass the charge current, protecting the

battery from overcharging.

V DD

S o la r

V OUT

C e ll T r

BATT

Load

H T 7 0 x x A -3

V SS

Rev. 1.00

9

April 18, 2013

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