AP3783

Document number: DS37429 Rev. 6 - 2

11 of 17

www.diodes.com

December 2015

© Diodes Incorporated

AP3783

Full load

38.9KHz

34%

57%

5.5%

12KHz

24.5KHz

68KHz

31.2KHz

45KHz

50KHz

55KHz

High Load

Medium

Load

Light Load

Ultra Light

Load

Figure 4. Multiple Segment Peak Current at CV Mode

It can be seen from Figure 4, with multiple segment peak current control, AP3783 power system can achieve good audible noise performance.

3-Segment Drive Current for Radiative EMI Suppression

When the power switch is turned on, a turn-on spike will occur, that worsens the radiative EMI. It is an effective way to decrease drive current

before gate voltage gets to miller platform. The AP3783 uses 3-segment drive current for radiative EMI suppression, as shown in Figure 5.

When gate voltage gets to 6V, the AP3783 drive current switches from low current (typical: 20mA) to high current (typical: 110mA). When the

gate voltage gets to 10V, the drive current will decrease gradually to 0mA until the gate voltage goes up to the clamp voltage (13V).

Gate voltage

Drive current

t

10V

6.5V

High drive current=110mA

Low drive current=20mA

13V

Miller Platform

Figure 5. Drive Current and Gate Voltage