RV5VH Datasheet, PDF (41/47 Pages) RICOH electronics devices division – DC/DC CONVERTER CONTROLLER

RV5VH3××
• Voltage Detector
RV5VH3××
R1
+
R2 ^Vref
–
Tr.1
R3
3 VDD Pull-up
Output Tr. ₈ DOUT
The Voltage Detector can operate by an input voltage to the VDD pin. The detector threshold and the reset voltage
are internally adjusted by trimmed resistors and the VD monitors VDD pin voltage.
The DOUT is Nch open-drain output and a pull up resistor is necessary.
Oepration Diagram
The output is pulled up to VDD voltage
12
3
Reset Voltage
+VDET
Detector Threshold –VDET
A
GND
Step
45
Comparator(+) Pin
B
Input Voltage
Hysteresis Range
Comparator Output
Tr. 1
Output Tr.
Step 1 Step 2 Step 3 Step 4 Step 5
A
B
B
B
A
H
L
L
LH
OFF ON ON ON OFF
OFF ON Indefinite ON OFF
Output Voltage
GND
R2+R3
A:
R1+R2+R3
R2
B:
R1+R2+R3
× _VDD
× _VDD
Step 1. Output Voltage is equal to Pull-up Voltage
Step 2. When Input voltage(VDD) reaches to the state of VREF≥VDD×(R2+R3)/(R1+R2+R3) at point A, the output of the comparator is reversed, so that the
output voltage becomes to GND.
Step 3. Output Voltage becomes indefinite when Power Source Voltage (VDD) is smaller than Minimum Operating Voltage. When the output is pulIed up,
Output becomes pull-up voltage and GND.
Step 4. Output Voltage becomes to GND.
Step 5. When Input voltage(VDD) reaches to the state of VREF≤VDD×R2/(R1+R2) at point B, the output of the comparator is reversed, so that the output voltage
becomes to pull-up voltage.
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