RV5VH Datasheet, PDF (21/47 Pages) RICOH electronics devices division – DC/DC CONVERTER CONTROLLER

RV5VH1××/RV5VH2××
• Voltage Detector
RV5VH1××/RV5VH2××
Ra
+
Rb ^Vref
–
Tr.1
Rc
VSEN
2
Output Tr. ₈ DOUT
Pull-up
The VD can operate by the voltage of “VOUT1”. The detector threshold and the reset voltage are internally adjusted by
trimmed resistors and the VD monitors VSEN pin voltage.
The DOUT is Nch open-drain output and a pull up resistor is necessary.
Oepration Diagram
VSEN pin is pulled up to VOUT1 voltage
12
3
Reset Voltage
+VDET
Detector Threshold –VDET
A
GND
Step
45
Comparator(+) Pin
B
Input Voltage
Hysteresis Range
Comparator Output
Step 1
A
H
Step 2 Step 3 Step 4 Step 5
B
B
B
A
L
L
L
H
Tr. 1
OFF ON ON ON OFF
Output Tr
OFF ON Indefinite ON OFF
Output Voltage
GND
Rb+Rc
A:
Ra+Rb+Rc
Rb
B:
Ra+Rb+Rc
× _VSEN
× _VSEN
Step 1. Output Voltage is equal to Pull-up Voltage.
Step 2. When Input voltage (VSEN) reaches the state of Vref≥VSEN×(Rb×Rc)/(Ra+Rb+Rc) at point A, the output of the comparator is reversed. so that the
output voltage becomes to GND.
Step 3. Output VoItage becomes indefinite when Power source Voltage (VSEN) is smaller than Minimum Operating VoItage. When the output is pulIed up,
Output becomes pull-up voltage and GND.
Step 4. Output VoItage becomes to GND.
Step 5. When input voltage(VSEN) reaches the state of Vref≤VSEN×Rb/(Ra+Rb) at point B, the output of the comparator is reversed, so that the output voltage
becomes to pull-up voltage.
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