Daattaasshheeeett
BM2PXX2F
(3-2) VCC Charge function
After VCC charge function operates once the VCC pin >VUVLO1 and the DC/DC operation starts then the VCC pin
voltage drops to <VCHG1. At that time the VCC pin is charged from DRAIN pin through start circuit.
By this operation, BM2PXX2 doesn’t occur to start failure.
When VCC pin voltage rises to VCC >VCHG2, charge is stopped. The operations are shown in figure 9.
VH
VUVLO1
VCHG2
VCC
VCHG1
VUVLO2
Switching
VH charge
charge
charge
charge
charge
OUTPUT
voltage
A
B C D E
F G H
Figure 9. Charge operation VCC pin charge operation
A: DRAIN pin voltage rises, charge starts to VCC pin by the VCC charge function.
B: VCC > VUVLO1, VCC UVLO function releases, VCC charge function stops, DC/DC operation starts.
C: When DC/DC operation starts, the VCC voltage drops.
D: VCC < VCHG1, VCC recharge function operates and VCC pin voltage rises.
E: VCC > VCHG2, VCC recharge function stops.
F: VCC < VCHG1, VCC recharge function operates and VCC pin voltage rises...
G: VCC > VCHG2, VCC recharge function stops.
H: After start of output voltage finished, VCC is charged by the auxiliary winding VCC pin stabilizes.
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TSZ02201-0F2F0A200040-1-2
7. Mar.2017.Rev.007
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