| Number of series cells | 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16 |
| Charge current (Max) (A) | 2 |
| Operating Vin (Max) (V) | 40 |
| Cell chemistry | Lead Acid |
| Battery charge voltage (Min) (V) | 0 |
| Battery charge voltage (Max) (V) | 20 |
| Absolute Vin (safety rating) (Max) ((V)) | 40 |
| Control interface | Standalone (RC-Settable) |
| Features | BAT temp thermistor monitoring (hot/cold profile) |
| Operating Vin (Min) (V) | 7.5 |
| Rating | HiRel Enhanced Product |
- 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
- APPLICATIONS
- Controlled Baseline
- One Assembly/Test Site
- One Fabrication Site
- Available in Military (–55°C/125°C) Temperature Range(1)
- Extended Product Life Cycle
- Extended Product-Change Notification
- Product Traceability
- Not to Exceed 185.35-KHz Oscillation Frequency at 125°C
(1) Additional temperature ranges available - contact factory
The UC2909 controls lead acid battery charging with a highly efficient average current mode control loop. This chip combines charge state logic with average current PWM control circuitry. Charge state logic commands current or voltage control depending on the charge state. The chip includes undervoltage lockout circuitry to insure sufficient supply voltage is present before output switching starts. Additional circuit blocks include a differential current sense amplifier, a 1.5% voltage reference, a –3.9-mV/°C thermistor linearization circuit, voltage and current error amplifiers, a PWM oscillator, a PWM comparator, a PWM latch, charge state decode bits, and a 100-mA open collector output driver.