MB39C811 Datasheet, PDF (10/36 Pages) Cypress Semiconductor – Ultra Low Power Buck PMIC Solar/Vibrations Energy Harvesting

MB39C811
7. Function
7.1 Operational Summary
Bridge Rectifier
The A/C voltage which is input to the AC1_1 and AC1_2 pins or the AC2_1 and AC2_2 pins is all-wave rectified at the
bridge rectifier of the low-dissipation diode. The bridge rectifier output is output from the DCOUT1 pin and the
DCOUT2 pin. By connecting those outputs to the VIN pin, the electric charge is accumulated to the capacitor and it is
used as the energy condenser of the buck converter.
Power Supply for Internal Circuit
When the VIN pin voltage is 3.5V or lower, the power supply is supplied from the VIN pin to the internal circuit directly.
If the VIN pin is over 3.5V, the internal regulator is activated and the power supply is supplied from the internal
regulator to the internal circuit. Therefore, the stable output voltage is maintained in the wide input voltage range 2.6 V
to 23V.
DC/DC Start-Up/Shut-Down
When the VIN pin voltage is over the release voltage VUVLOH for the under voltage lockout protection circuit (UVLO),
the converter circuit is enabled and the electric charge is supplied from the input capacitor to the output capacitor.
When the V^IN pin voltage is below the UVLO detection voltage VUVLOL, the converter is disabled. The 12V hysteresis
between the release voltage and the detection voltage for UVLO prevents the converter from noise or frequent
ON/OFF which is caused by the VIN pin voltage-drop during start-up.
Sleep/Auto Active Control
When the feedback voltage VFB for the converter reaches the determinate voltage, the sleep state to stop the
switching operation starts and that can reduce the consumption power from the internal circuit. When the VOUT voltage
is below the threshold value, the VOUT voltage is maintained to the rated value by making the converter active again.
Document Number: 002-08401 Rev *A
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