S-882Z Seiko Instruments, S-882Z Datasheet - Page 8

• Manufacturer Part Number: S-882Z
• Description: ULTRA-LOW VOLTAGE OPERATION CHARGE PUMP IC
• Manufacturer: Seiko Instruments

www.DataSheet.co.kr
8
ULTRA-LOW VOLTAGE OPERATION CHARGE PUMP IC FOR STEP-UP DC-DC CONVERTER STARTUP
S-882Z Series
Operation
1. Basic Operation : IC with 2.0 V Discharge Start Voltage
Caution When stopping the discharge to OUT pin and recharging a startup capacitor (C
(1) In the S-882Z Series, when power of 0.3 V or higher is input to the VIN pin, the oscillation circuit starts
(2) The charge pump circuit is driven by this CLK signal, and the power of the VIN pin is converted to the
(3) The stepped up electric power output from the charge pump circuit is gradually charged to the startup
(4) When the CPOUT pin voltage (V
(5) When M1 switches on, the step up electric power charged to C
(6) When V
(7) When the VM pin voltage (V
(8) When V
the comparator (COMP2) changes from low level to high. As a result, the oscillation circuit stops operation
and the shutdown state is entered.
operation with that power, and the CLK signal is output from the oscillation circuit.
stepped up electric power in the charge pump circuit.
capacitor (C
signal of the comparator (COMP1) changes from high level to low. As a result, the discharge control switch
(M1), which was off, turns on.
switches off, and the discharge is stopped.
recharged to C
VIN
needed to be charged until CPOUT pin voltage (V
voltage (V
4
CPOUT
VM
does not reach V
CPOUT
Condition: Out pin voltage (V
declines to the level of the discharge stop voltage (V
CPOUT
CPOUT2
) connected to the CPOUT pin and the voltage of the CPOUT pin gradually rises.
Charging
. (Retun to the operation specified in (3) .)
Oscillation
Charge pump circuit
). In this case, set the condition as follows:
circuit
CLK signal
VM
OFF
) reaches or exceeds the shutdown voltage (V
CPOUT
VSS
or more, the stepped up electric power from the charge pump circuit is
Seiko Instruments Inc.
Figure 12 Operation Diagram
EN −
) reaches or exceeds the discharge start voltage (V
2
OUT
CPOUT
)<Discharge stop voltage (V
5
CPOUT
CPOUT
C
V
CPOUT
REF
) is lowered less than discharge stop
CPOUT2
is discharged from the OUT pin.
COMP1
COMP2
−
+
−
+
) as the result of the discharge, M1
CPOUT2
OFF
), the output signal (EN−) of
Detection
)
M1
Discharging
CPOUT1
CPOUT
Rev.1.2
1
3
), the output
), C
OUT
VM
CPOUT
_00
is
Datasheet pdf - http://www.DataSheet4U.net/