Description
The UC3909 family of Switchmode Lead-Acid Battery Chargers accuratelycontrols lead acid battery charging with a highly efficient average currentmode control loop. This chip combines charge state logic with average currentPWM control circuitry. Charge state logic commands current or voltagecontrol depending on the charge state. The chip includes undervoltagelockout circuitry to insure sufficient supply voltage is present before outputswitching starts. Additional circuit blocks include a differential current senseamplifier, a 1.5% voltage reference, a –3.9mV/°C thermistor linearizationcircuit, voltage and current error amplifiers, a PWM oscillator, a PWM comparator,a PWM latch, charge state decode bits, and a 100mA open collectoroutput driver.
- Accurate and Efficient Control of Battery Charging
- Average Current Mode Control from Trickle to Overcharge
- Resistor Programmable Charge Currents
- Thermistor Interface Tracks Battery Requirements Over Temperature
- Output Status Bits Report on Four Internal Charge States
- Undervoltage Lockout Monitors VCC and VREF
