1365

XC9510

Series

●

Application Information (Continued)

7. With the DC/DC converter of the IC, the peak current of the coil is controlled by the current limit circuit. Since the

peak current increases when dropout voltage or load current is high, current limit starts operating, and this can lead

to instability. When peak current becomes high, please adjust the coil inductance value and fully check the circuit

operation. In addition, please calculate the peak current according to the following formula:

8. When the peak current, which exceeds limit current flows within the specified time, the built-in driver transistor is

turned off (the integral latch circuit). During the time until it detects limit current and before the built-in transistor

can be turned off, the current for limit current flows; therefore, care must be taken when selecting the rating for the

coil or the Schottky diode.

resistance of the coil.

more.

11. Use of the IC at voltages below the recommended voltage range may lead to instability.

12. This IC and the external components should be used within the stated absolute maximum ratings in order to prevent

damage to the device.

13.

Since the DC/DC converter and the regulator of the XC9510 series are connected in series, the sum of the output

converter. Please be careful of the power dissipation when in use. Please calculate power dissipation by using the

following formula.

Pd=PdDC/DC + PdVR

RON: ON resistance of the built-in driver transistor to the DC/DC (= 0.5Ω<TYP.>)

RON=Rpon x P-chOnDuty / 100

+ Rnon x (1 – P-chOnDuty / 100)

voltage and VR output pin voltage. For the XC9510B/C/E/F/K/L series, which voltage detector circuit monitors the

DC/DC output pin voltage and the VR output pin voltage, please determine the detect voltage value (VDF) by the

following equation.

(The VD detect voltage and hysteresis range).

■

NOTES ON USE (Continued)