參數(shù)資料
型號(hào): XC9508_1
廠商: TOREX SEMICONDUCTOR LTD.
英文描述: Synchronous Step-Down DC/DC Converter with Built-In LDO Regulator in Series Plus Voltage Detector
中文描述: 同步降壓型DC / DC轉(zhuǎn)換器,配有穩(wěn)壓器在系列脈沖電壓檢測(cè)器調(diào)節(jié)器
文件頁(yè)數(shù): 13/38頁(yè)
文件大小: 2943K
代理商: XC9508_1
13/38
XC9508
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:
Peak current: Ipk = (V
IN
- D
COUT
)
×
OnDuty / (2
×
L
×
Fosc) + I
DOUT
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.
9. When V
IN
is low, limit current may not be reached because of voltage falls caused by ON resistance or serial
resistance of the coil.
10. In the integral latch circuit, latch time may become longer and latch operation may not work when V
IN
is 3.0V or
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 XC9508 series are connected in series, the sum of the output
current (I
DOUT
) of the DC/DC and the output current (I
ROUT
) of the VR makes the current flows inside the DC/DC
converter. Please be careful of the power dissipation when in use. Please calculate power dissipation by using
the following formula.
Pd=PdDC/DC + PdVR
DC/DC power dissipation (when in synchronous operation) :
PdDC/DC = I
DOUT
2
×
RON
VR power dissipation:
PdVR=(D
COUT
– V
ROUT
)
×
IR
OUT
RON: ON resistance of the built-in driver transistor to the DC/DC (= 0.5
Ω
<TYP.>)
RON=Rpon
×
P-chOnDuty / 100 + Rnon
×
(1 – P-chOnDuty / 100)
14. The voltage detector circuit built-in the XC9508 series internally monitor the V
DD
pin voltage, the DC/DC output pin
voltage and VR output pin voltage. Please determine the detect voltage value (V
DF
) by the following equation.
V
DF
(Setting voltage on both the D
COUT
voltage and the V
ROUT
voltage)
×
85%*
* An assumed value of tolerance among the D
COUT
voltage, the V
ROUT
voltage, and the VD release voltage
(The VD detect voltage and hysteresis range).
NOTES ON USE (Continued)
相關(guān)PDF資料
PDF描述
XC9509A033AL Synchronous Step-Down DC/DC Converter with Built-In LDO Regulator in Parallel Plus Voltage Detector
XC9509A033AR Synchronous Step-Down DC/DC Converter with Built-In LDO Regulator in Parallel Plus Voltage Detector
XC9509A033DL Synchronous Step-Down DC/DC Converter with Built-In LDO Regulator in Parallel Plus Voltage Detector
XC9509A033DR Synchronous Step-Down DC/DC Converter with Built-In LDO Regulator in Parallel Plus Voltage Detector
XC9509A036AL Synchronous Step-Down DC/DC Converter with Built-In LDO Regulator in Parallel Plus Voltage Detector
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