HT7627 查看數據表（PDF） - Holtek Semiconductor
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HT7627 Datasheet PDF : 6 Pages
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HT7627
Pin Description
Pin No.
Pin Name
1, 3, 7
NC
2
LX
4
VSS
5
CP
6
VDET
8
VOUT
I/O
Description
¾ No connection
I Switching pin
¾ Negative power supply, ground
I External capacitor for adjusting VDET output delay time.
O Voltage detector open drain output (needs a pull-high resistor)
O DC/DC converter voltage output
Absolute Maximum Ratings
Supply Voltage ............................ VSS-0.3V to VSS+6V
Switching pin Voltage .................. VSS-0.3V to VSS+6V
Power Consumption ........................................ 150mW
Storage Temperature .......................... -40°C to 125°C
Operating Temperature ......................... -25°C to 70°C
Note: These are stress ratings only. Stresses exceeding the range specified under ²Absolute Maximum Ratings² may
cause substantial damage to the device. Functional operation of this device at other conditions beyond those
listed in the specification is not implied and prolonged exposure to extreme conditions may affect device reliabil-
ity.
Electrical Characteristics
Symbol
VOUT
VIN
Vstart
Vhold
Iin
ILX
ILEAK
fOSC
VDET
VHYS
IDETOL
Parameter
Output Voltage
Input Voltage
Starting Voltage
Voltage Hold
Current Consumption
LX Switching Current
LX Leakage Current
Oscillator Frequency
H®L Detectable Voltage
L®H Detectable Voltage
Hysteresis Width
VDET Output Sink Current
Test Conditions
¾
¾
L=330mH, IL=1mA
¾
Measure at no load
VIN=1.5V
¾
VIN=1.5V
¾
¾
¾
VOUT=2.2V, VDET=0.2V
Min.
2.56
¾
¾
0.9
¾
60
¾
¾
2.0
2.2
¾
0.5
Ta=25°C, VOUT=2.7V
Typ. Max. Unit
2.7
2.75
V
¾
5
V
0.95
1.1
V
¾
¾
V
14
20
mA
¾
¾
mA
¾
1
mA
139
¾
kHz
2.1
2.2
V
2.3
2.4
V
0.2
¾
V
¾
¾
mA
Functional Description
Operation of step-up DC/DC converter
The following figures show the basic circuit configura-
tion of the step-up operation of the IC. In the configura-
tion, when the transistor tr is entirely Off, the output
voltage is the value of the input voltage VIN minus the
voltage reduced by inductor L and Schottky diode SD.
When tr has been On for time ton and is suddenly turned
Off, voltage VL is generated at the edges of L because of
the energy accumulated during the ton period. There-
fore, the peak value of the voltage generated at that time
is VIN+VL, and it is stored in the output capacitor CL via
SD. This generates the step-up output voltage VOUT that
is larger than VIN.
Rev. 1.00
2
January 18, 2002
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