DS2711/DS2712: Loose Cell NiMH Charger

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DS2712 Parallel Charge Configuration with Switch-Mode Charge Current Regulation

The example in Figure 5 uses the DS2712 to regulate charge current as a switching (buck) regulator. ICHG is set

to 2A using RSNS = 0.056

Ω. The effective charge current for each cell is ICHG x 0.484 = 968mA. The CSOUT

comparator output switches OFF when the voltage across the sense resistor goes above 0.125V and back ON

when the voltage drops below 0.100V. In this mode, the operating frequency is determined primarily by the value of

the inductor, the hysteresis, the input voltage, and the voltage on the cells. In some cases, a damping network may

be required to prevent overshoot with the batteries removed.

Figure 5. PARALLEL CONFIGURATION WITH SWITCH-MODE CURRENT

REGULATION (DS2712 ONLY)