MPQ2169B

– 6V, DUAL 1.4A/1.4A OR 2A/0.8A SYNC BUCK REGULATOR, AEC-Q100

MPQ2169B Rev. 1.0

MonolithicPower.com

20

12/20/2021

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Low-Side (LS) Current Limit Protection

The MPQ2169B has a -1A low-side (negative)

current limit. Once IL reaches the current limit,

the LS-FET immediately turns off and the HS-

FET turns on. The current limit prevents the

negative current from dropping too low and

possibly damaging the components.

Dropout Operation

The MPQ2169B allows the HS-FET to remain

on for more than one switching cycle, and

increases the duty cycle while VIN drops down

to VOUT. When the duty cycle reaches 100%,

the HS-FET turns on to deliver current to the

output up to its current limit. VOUT is then the

difference between VIN, the voltage drop across

the main switch, and the inductor.

Thermal Shutdown

The MPQ2169B employs thermal protection by

internally monitoring the IC temperature, which

prevents the chip from operating at exceedingly

high temperatures. If the junction temperature

exceeds the threshold value (typically 175°C),

the whole chip shuts down. There is a 40°C

hysteresis.

Once

the

junction

temperature

drops to about 135°C, the device initiates a soft

start and resumes normal operation. This is a

non-latch protection.