XC9510A1333 TOREX [Torex Semiconductor], XC9510A1333 Datasheet - Page 13

• Manufacturer Part Number: XC9510A1333
• Description: Synchronous Step-Down DC/DC Converter With Built-In LDO Regulator Plus Voltage Detector
• Manufacturer: TOREX [Torex Semiconductor]

■NOTES ON USE (Continued)
●Application Information (Continued)
10. In the integral latch circuit, latch time may become longer and latch operation may not work when V
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
13.
14. The voltage detector circuit built-in the XC9510 series internally monitor the V
7. With the DC/DC converter of the IC, the peak current of the coil is controlled by the current limit circuit. Since the
8. When the peak current, which exceeds limit current flows within the specified time, the built-in driver transistor is
9. When VI
current (ID
converter. Please be careful of the power dissipation when in use. Please calculate power dissipation by using the
following formula.
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:
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.
Since the DC/DC converter and the regulator of the XC9510 series are connected in series, the sum of the output
DC/DC power dissipation (when in synchronous operation) : PdDC/DC = ID
Pd=PdDC/DC + PdVR
VR power dissipation: PdVR=(DC
more.
damage to the device.
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.
VDF≦(Setting voltage on both the DC
* An assumed value of tolerance among the DC
RON: ON resistance of the built-in driver transistor to the DC/DC (= 0.5Ω<TYP.>)
RON=Rpon x P-chOnDuty / 100
Peak current: Ipk = (V
(The VD detect voltage and hysteresis range).
N
OUT
is low, limit current may not be reached because of voltage falls caused by ON resistance or serial
) of the DC/DC and the output current (IR
+ Rnon x (1 – P-chOnDuty / 100)
IN
- DC
OUT
OUT
) x OnDuty / (2 x L x Fosc) + ID
– VR
OUT
OUT
voltage and the VR
) x IR
OUT
OUT
voltage, the VR
OUT
) of the VR makes the current flows inside the DC/DC
OUT
OUT
voltage)×85%*
OUT
OUT
2
x RON
voltage, and the VD release voltage
DD
pin voltage, the DC/DC output pin
IN
is 3.0V or
XC9510
13/36
Series