MP9184 – 17A, 600KHZ, 20V WIDE INPUT RANGE ,SYNCHRONOUS BOOST CONVERTER IN ASMALL 3X4MM QFN PACKAGE

MP9184 Rev. 1.0

www.MonolithicPower.com

13

8/27/2015

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mode. If the sampled current signal rises to

100mV

(within

the

1.1ms

blank

time),

immediately the MP9184 operates in hiccup

mode.

The MP9184 starts switching in internal current-

sense mode after it detects 0V on MODE. In

external current-sense mode, MP9184 detects

MODE voltage and starts switching (after

MODE is higher than Vin + 2V). In over-current

or hiccup mode, MODE is pulled low. If the

average current limit is triggered before

switching, MP9184 may not start switching

because MODE is regulated to low in an

overload condition.

If the peak-inductor current is higher than 6A,

an

external

current-sensing

resistor

is

recommended. Do NOT change the sensing

configuration when MP9184 is in operation.

Light-Load Operation

To optimize efficiency at light load, MP9184

employs a pulse-skipping mechanism and

foldback frequency. When the load becomes

lighter, the COMP voltage decreases, causing

the MP9184 to enter foldback operation (the

lighter the load, the lower the frequency).

However, if the load becomes exceedingly low,

MP9184 enters PSM. PSM operation is

optimized so that only one SW pulse is

launched every burst cycle; therefore the output

ripple is very low.

Enable (EN) and Programmable UVLO

EN enables and disables the MP9184. When

applying voltage higher than the EN higher

threshold (1V, typically), MP9184 starts up

some of the internal circuits (micro-power

mode). If EN voltage exceeds the turn-on

threshold (1.33V), the MP9184 enables all

functions and starts boost operation. Boost

operation is disabled when EN voltage falls

below

its

lower

threshold

(1.33V).

To

completely shut down the MP9184, <0.4V low-

level voltage is required on EN. After shutdown,

MP9184 sinks a current from input power (less

than 1uA, typically).

The maximum recommended voltage on EN is

5.5V. If the EN control signal comes from a

voltage higher than 5.5V, a resistor should be

added between EN and the control source. An

internal Zener diode on EN clamps the EN

voltage to prevent runaway. Ensure the Zener

clamped current flowing into EN is less than

0.3mA.

Meanwhile, EN can program Vin’s UVLO (see

“Applications\UVLO Hysteresis” section).

Thermal Shutdown (TSD)

To prevent thermal damage, the device has an

internal

temperature

monitor.

If

the

die

temperature exceeds 150°C, the converter

shuts down. Once the temperature drops below

125°C, the power supply resumes operation

.