Circuit Description
The CS1107 relay driver IC provides up to 350mA of drive
are only reported when the Control pin is high, due to the
low quiescent current when the Control pin is low and the
output device is turned off.
current in a low-side configuration. The Output driver pin
is controlled through the TTL compatible Control input
pin. A high condition on the Control pin turns the output
pin on.
Overcurrent protection is provided by duty cycle control.
When the Output current exceeds the current limit thresh-
old, the output enters duty cycle mode to reduce power
dissipation of the IC to a safe level. The higher the thresh-
old is exceeded the lower the duty cycle becomes.
Fault
The
overtemperature conditions on the IC. If a fault is present,
Fault
pin reports short circuit, open circuit, and
the open collector output
pin will be low. Typical
numbers for faults are: exceeding 500mA of drive current
will report a short circuit. Less than 40mA (typical) will
report an open circuit. A temperature fault will be reported
when the die temperature exceeds 180¡C (typical). Faults
A 33V on-chip zener diode on the Output pin protects the
device from flyback pulses when a relay is turned off. The
saturation voltage of this pin will not exceed 1.5V at
350mA.
Applications Diagram
Gnd
Output
CS1107
C
MODULE(ESD)
10nF
V
Gnd
Gnd
Gnd
CC
Fault
20k
Control
VBAT
V
CC
microprocessor
3
CHERRY [ CHERRY SEMICONDUCTOR CORPORATION ]
