www.belling.com.cn

5

BL9384

FUNCTIONAL DECRIPTIONS

Loop Operation

The BL9384 is a wide input range, high-efficiency, DC-to-DC step-down switching regulator, capable of delivering up to

3A of output current, integrated with a 110m

Ω synchronous MOSFET, eliminating the need for external diode. It uses a

PWM current-mode control scheme. An error amplifier integrates error between the FB signal and the internal reference

voltage. The output of the integrator is then compared to the sum of a current-sense signal and the slope compensation

ramp. This operation generates a PWM signal that modulates the duty cycle of the power MOSFETs to achieve regulation

for output voltage.

Current Limit

There is a cycle-by-cycle current limit on the high-side MOSFET of 3A(typ). When the current flowing out of SW exceeds

this limit, the high-side MOSFET turns off and the synchronous rectifier turns on. Unlike the traditional method of

current limiting by limiting the voltage at the compensation pin, which usually has large variation due to duty cycle

variance, this type of peak current limiting scheme provides a relatively more accurate limit for output current, thereby

lowering the requirements for system design.

COMPONENT SELECTRION

When setting up the BL9384 for different output voltage, please use following recommended component value for the

best performance.

µF)

L (

µH)

8

22x2

22

5

22x2

15

3.3

22x2

10

2.5

22x2

6.8

1.8

22x2

4.7

1.2

22x2

3.3