U2403B

` Easy-to-run autonomous dual rate charger
` Constant charge current
` 3 h 24 h charge time programmable
` Low cost dc regulator
` Overtemperature protection
` Charge-mode indication
` Operation starts at the moment of battery insertion
` Fast charge time-test mode

· Cordless telephones
· Low-cost battery-charge timer
· Entertainment

The U2403B is a monolithic, integrated-bipolar circuit which can be used in applications for time-controlled, constant-current charge. Selection of charge current versus timing is carried out by using the external circuit at Pins 2, 3 and 4. For high current requirement, an external transistor is recommended in series with the battery. To protect the U2403B IC against high power loss (typically > 140°C), the oscillator is shut down when the reference voltage is switched off (0 V). The latter also takes place when there is a saturation caused by collector voltage at Pin 1. When the overtemperature has disappeared and the collector voltage at Pin 1 has exceeded the supply voltage (V₁ > V_S), charge time operation continues (see flow chart in figure 3).