Seiko Instruments Temperature Sensor IC Provides PWM Output Signal
Seiko Instruments introduced the S-5855A Series, a 1-wire PWM output temperature sensor IC. Developed in CMOS technology low current consumption of only 50µA is one of its merits. It changes the duty cycle of a frequency, preset with a single capacitor, according to ambient temperature. The available temperature sensitivities which have to be determined at the time of order are -1%/°C, -2%/°C, -3%/°C and -4%/°C.
The starting temperature at which the S-5855A temperature sensor will start to modulate its output signal is also determined at the time of order. It may be selected from +40°C up to +80°C in 10°C increments. The duty cycle decreases from 100% when the starting temperature is exceeded by the predetermined percentage per degree C and this decrease is linear against the temperature rise.
The primary application for this integrated circuit series is the over-temperature protection of LED lighting as it finds use in flat TV sets and computer LCD monitors. A wide range of applications can be found wherever equipment needs protection against overheating and the heating power can be reduced by reduction of the duty cycle of energy supply. This also is a generally possible range of applications where LEDs are used to make up for lamps or any other lighting purpose. CMOS and N-ch open drain are available as output form. The small packages SNT-4A and SOT-23-5 it comes in enable high-density mounting.
