GND

CT

RESET

R1

R2

RESET

GND

SENSE

TL7700

SLVS220F

– JULY 1999 – REVISED AUGUST 2011

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DETAILED DESCRIPTION

Sense-Voltage Setting

The SENSE terminal input voltage, Vs, of the TL7700 typically is 500 mV. By using two external resistors, the

circuit designer can obtain any sense voltage over 500 mV. In Figure 19, the sensing voltage, Vs

', is calculated

as:

Where:

[

Figure 19.

Sense-Voltage Hysteresis Setting

resetting of TL7700 is unstable. Hysteresis is added to the sense voltage to prevent such problems. As shown in

Where:

At room temperature, Is has variations of 2.5 mA

variations of (

±0.5 × R1) mV. In circuit design, it is necessary to consider the voltage-dividing resistor tolerance

10

Copyright

© 1999–2011, Texas Instruments Incorporated