PM6675STR datasheet(37/53 Pages) STMICROELECTRONICS

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PM6675S

Device description

37/53

Figure 46.

Maximum LDO source able output current vs input voltage

7.2.2

LDO section soft-start

The LDO section soft-start is performed by clamping the current limit. During startup, the

LDO current limit voltage is set to 1A and the output voltage increases linearly. When the

output voltage rises above 90 % of the nominal value, the current limit is released to 2 A

according to the LILIM pin setting. At the end of the ramp-up phase of the soft-start, the LPG

signal is masked for about 100

µs in order to ignore dynamic overshoot on the feedback pin.

7.2.3

LDO section power good signal

The LPG pin is an open drain output used to monitor the LDO output voltage through LFB

pin.

The LPG signal is held low if the output voltage drops 10 % below or rises 10 % above the

nominal regulated value. The LPG output can sink current up to 4 mA.

7.2.4

LDO section output discharge

Active soft-end of the LDO output occurs when the LEN (Linear ENable) is forced low. When

the LDO section is turned off, an internal 25

Ω resistor, directly connected to the LOUT pin,

discharges the output.

Figure 47.

LDO section soft-end

0.0

0.2

0.4

0.6

0.8

1.0

1.2

1.4

1.6

1.8

2.0

2.2

0.0

0.5

1.0

1.5

2.0

2.5

3.0

3.5

4.0

4.5

5.0

VLIN [V]

VOUT=1.05V

VOUT=1.2V

VOUT=1.5V

VOUT=1.8V

VOUT=2.0V

VOUT=2.2V

VOUT=2.5V

VOUT=3.3V

LEN

VLDO

Resistive Discharge

PM6675STR 数据表(PDF) 37 Page - STMicroelectronics

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