MP5600EU datasheet(16/26 Pages) MPS

16 / 26 page

MP5600-COMPACT MULTIPLE-OUTPUT POWER SUPPLY FOR TV-LCD PANEL

MP5600 Rev. 0.9

www.MonolithicPower.com

10/19/2009

MPS Proprietary Information. Unauthorized Photocopy and Duplication Prohibited.

Figure 5 Positive Charge Pump Block Diagram

When EN2 is logic-high, An internal 6uA current

source begins to charge the DLY2 capacitance,

positive charge pump will be enabled when the

voltage on the capacitor is higher than 1.2V.

Each time when it is enabled, the positive

charge-pump regulator goes through a soft-start

routine by ramping up its internal reference

voltage from 0 to 1.2V in 128 steps. The soft-start

period is 4ms (fsw=450kHz) and FBP fault

detection is disabled during this period.

Gate Pulse Management

Gate pulse management section consists of P-

channel MOSFET: M6 is between GPH pin and

GPO pin. M7 is between GPO pin and GPD pin.

The GPM section is enabled when VDLY4 exceeds

1.2V. There are two different operation modes:

mode 1 and mode 2. See figure 6.

Figure 6 Gate Pulse Management Block Diagram

Mode 1 is selected by connecting the MODE pin

to VCC. When GPI is high, GPO is connected to

GPH through M6. When GPI is low, GPO is

connected to GPD through M7. Then GPO is

discharged through a resistor connected between

GPD and GND. And the discharging of GPO is

stop when VGPO reaches 10 times of the voltage

on GPT pin programmed by the external resistive

divider. See figure 7.

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