Different Pwm Frequencies ( 1Hz And 32 Hz) - Nokia NSE-6 SERIES Service Manual

NSE–6
System Module

Different PWM Frequencies ( 1Hz and 32 Hz)

When a travel charger (2– wire charger) is used, the power switch is
turned ON and OFF by the PWM input when the PWM rate is 1Hz. When
PWM is HIGH, the switch is ON and the output current Iout = charger cur-
rent – CHAPS supply current. When PWM is LOW, the switch is OFF and
the output current Iout = 0. To prevent the switching transients inducing
noise in audio circuitry of the phone soft switching is used.
The performance travel charger (3– wire charger) is controlled with PWM
at a frequency of 32Hz. When the PWM rate is 32Hz CHAPS keeps the
power switch continuously in the ON state.
SWITCH
PWM (1Hz)
SWITCH
PWM (32Hz)
Page 3 – 20
ON OFF
ON
Technical Documentation
ON OFF
PAMS
ON
Original 08/98