The ZXSC440 is a dedicated photoflash charger, charging an 80μF photoflash capacitor to 300V in 3.5 seconds from a 3V supply. The flyback conversion efficiency is typically 75%, much higher than the commonly used discrete charging circuits. The Charge pin enables the circuit to be initiated from the camera's microprocessor, using negligible current when flash is not being used. The Ready pin signals the microprocessor when the flash is charged and ready to be fired. A small amount of hysteresis on the voltage feedback shuts down the device as long as the capacitor remains fully charged, again using negligible current. Applications include digital camera flash unit and film camera flash unit.
The ZXSC440 is a dedicated photoflash charger designed for digital and film camera flash units. It charges an 80 µF capacitor to 300 V in 3.5 seconds from a 3 V supply and provides a charge‑ready signal to the camera micro‑processor while drawing negligible current when idle.
The device operates from a 1.8 V‑8 V supply, tolerates –40 °C to +85 °C, and includes pins for DRIVE, CHARGE, READY, SENSE, and VEE. Electrical characteristics such as quiescent current (220 µA), shutdown current (45 µA), drive current (3.4‑5 mA), and efficiency (typical 75 %, up to 85 %) are detailed, along with a typical application circuit and transformer specifications.
| Charging voltage | 300 V |
|---|---|
| Charge time | 3.5 s |
| Operating temperature range | -40 °C – +85 °C |
| Efficiency (typical) | ≈ 75 % |
| Efficiency (max test) | 85 % |
| Feedback voltage | 300 mV (typical) |
| Power dissipation (25 °C) | 450 mW |
The charger reaches 300 V in about 3.5 seconds.