The LP64930 operates by a constant frequency, current mode architecture. The output voltage is set by an external divider returned to the FB pin. An error amplifier compares the divided output voltage with a reference voltage of 0.6V and adjusts the peak inductor current accordingly.

Thermal Protection   LP64930同步整流車充3.6A方案芯片

The total power dissipation in LP64930 is limited by a thermal protection circuit. When the device temperature rises to approximay +150 ℃ , this circuit turns off the output, allowing the IC to cool. The thermal protection circuit can protect the device from being damaged by overheating in the event of fault conditions. Continuously running the LP64930 into thermal shutdown degrades device reliability.

Current Limit   LP64930同步整流車充3.6A方案芯片

The Current limit is set by outside resistance (RSEN), When the CS voltage larger than 53mV/65mV, the current limit is happened that driver can be turned off. The current limit set according to the following equation:

IOUT  = VCS  / RSEN

Setting Output Voltage

The output voltage is set with a resistor divider from the output node to the FB pin. It is recommended to use divider resistors with 1% tolerance or better. To improve efficiency at very light loads consider using larger value resistors. If the values are too high the regulator is more susceptible to noise and voltage errors from the FB input current are noticeable. For most applications, a resistor in the 10k? to 1M? range is suggested for RUP and RDN. The output voltage is established by the following equations

VOUT = 0.6V •（1 + RUP / RDN）

Where VREF is 0.6V.   

Output Cable Resistance Compensation

To compensate for resistive voltage drop across the charger's output cable, the LP64930 integrates a simple, user-programmable cable voltage drop compensation using the impedance at the FB pin. The delta VOUT rises when the feedback resistance RSEN value rises, use the equation below:

ΔVOUT(V)=IOUT(A)•RSEN(mΩ)•RUP(KΩ) /40 KΩ