HT46R52A is an application for nickel-hydrogen battery chargers, featuring constant current charging, discharge selection, and automatic charging stop.
The HT46R52A is a Holtek‑based charging circuit designed for rechargeable NiMH batteries used in portable devices such as mobile phones, digital cameras, and MP3 players. It provides both slow (70 mA) and fast (≈70 mA) charging modes with automatic termination after six hours.
The charger uses PWM output and a 4‑channel 12‑bit ADC to monitor battery voltage and current. LED colors indicate the current state: red and yellow for fast charging, red only for slow charging, and both off while waiting for a battery. The firmware includes initialization, fast‑charge, slow‑charge, and timer‑interrupt routines to control the charging process. This manual is written in Chinese.
| Slow charge current | 70 mA |
|---|---|
| Fast charge current | ≈70 mA |
| Discharge current | 50 mA |
| Maximum charging time | 6 hours |
| ADC resolution | 1.2 mV (12‑bit) |
| PWM output | Provided by HT46RS2A |
| Number of ADC channels | 4 |
The charger stops charging after six hours.
If the battery voltage exceeds 1.2 V, the charger enters fast‑charge mode; otherwise it uses slow‑charge.
The slow‑charge current is 70 mA, and the fast‑charge current is about 70 mA (specified as 7SmA in the document).