BD8158FVM are the 1 channel step-up switching regulator which builds in the low voltage FET. Input voltage is 2.1V to 4.0V realizing the low consumption power. High accuracy feedback voltage ±1% is established and the brightness dispersion of TFT-LCD panel is suppressed.Current mode PWM systemInput voltage is 2.5V to 5.5VSwitching frequency is variable as 600kHz / 1,200kHz.Built-in 0.25Ω power switchFeedback voltage 1.245±1%Built-in under-voltage lockout protection circuitBuilt-in overcurrent protection circuitBuilt-in thermal shutdown circuit