The DD30CRTA is a PWM switch-mode battery charger controller for a 12V lead-acid battery in a small package using a few external components. The DD30CRTA is specially designed for charging 12V lead-acid battery with trickle charge, constant current charge, over-charge and float charge mode. In over-charge and float charge mode, the regulation voltage is internally set.

The constant charge current is programmable with a single sense resistor.

 Deeply discharged batteries are automatically trickle charged at 17.5% of the programmed constant charge current until the cell voltage exceeds 75% of the regulation voltage in over-charge mode. The over-charge is terminated once the charging current drops to 38% of the constant charge current, then DD30CRTA will enter float charge mode. A new charge cycle automatically restarts if the battery voltage falls below 83.95% of the over-charge voltage in float-charge mode. DD30CRTA will automatically enter sleep mode when the input voltage is lower than the battery voltage.

Other features include under-voltage lockout and indication, etc.

1: The Regulation Voltage in Over Voltage Mode and Float Charge Mode

The regulation voltage VOC at BAT pin in overcharge mode is set at 14.8V(Typical) with ±1.5% accuracy.

In float charge mode, the regulation voltage VFLOAT at BAT pin is 91.57% of that in overcharge mode, which is 13.55V(Typical).

Trickle Charge Mode At the beginning of a charge cycle, if the battery voltage is below 75%×VOC, the charger goes into trickle

charge mode with the charge current set at about 17.5% of the constant current.

2: End-of-Over Charge Current

When the battery voltage approaches the over-charge voltage, the charger goes into the overcharge mode. In

overcharge mode, the charge current start to decrease and when the charge current drops to 38% of constant

charge current, the charger goes into float-charge mode.

3: Float Charge Mode

After the overvoltage charge is terminated, the charger goes into float charge mode. In float charge mode, the

battery voltage is regulated to 91.57%×VOC, namely 13.55V(Typical). Float charge mode can compensate for

the loss of battery power due to self-discharge or external loading.

4: Automatic Battery Recharge

In float mode, if both the battery and the input power supply (wall adapter) are present, a new charge cycle will

begin if the battery voltage drops below 83.95%×VOC due to self-discharge or external loading.

A new charge cycle can also be started manually by plugging off the input supply and reapplying it.

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Application:

1. Car battery charging
2. Solar battery charging
3. Loudspeaker
4. Lead-Acid Battery Charger
5. Electric Bicycle Charger
6. UPS
7. Portable Industrial and Medical Equipment
8. Standalone Battery Chargers