BL8080
Over Temperature Protection (OTP)
BL8080 integrates a temperature detection circuit
that will shut down PWM output when the junction
temperature exceeds 135℃. s When the
temperature drops down and the VCC voltage is
still over the UVLO voltage, the device resumes
operation.
Under Voltage Lockout (UVLO)
The turn-on and turn-off threshold voltage are
fixed internally at 8.8V and 4.5V, respectivelly.
ICC
Supply Current(mA)
external transistor to enable the BL8080. The
hold-up capacitor
supplies VCC until the
auxiliary winding of transformer takes over. When
VCC drops below 4.5V, BL8080 stops work. This
UVLO hysterisis ensures that the hold-up
capacitor is adequate to supply VCC during
normal operation.
Built-in Slope Compensation
The voltage across the current sense resistor is
collected for current mode control and cycle by
cycle current limit. Built-in slope compensation
improves the stability and prevents sub-harmonic
oscillations when the device works in continue
conduction mode -especially when the duty cycle
exceeds 50%.
Turn Off
Turn On
4.5
8.8
Supply Voltage(V)
VCC
Figure12. UVLO of BL8080
During start up, the hold-up capacitor should be
charged up to 8.8V by the start up resistor and
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