MP8714 – 17V, 10A, SYNCHRONOUS, STEP-DOWN CONVERTER

MP8714 Rev.1.0

www.MonolithicPower.com

12

12/27/2016

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OPERATION

The MP8714 is a high-frequency, synchronous,

rectified, step-down, switch-mode converter

with built-in power MOSFETs. The MP8714

offers a very compact solution that achieves

10A of output current with excellent load and

line regulation over a wide input supply range.

The MP8714 has three working modes:

continuous conduction mode (CCM), advanced

asynchronous modulation (AAM) mode, and

discontinuous conduction mode (DCM).

CCM Control Operation

In continuous conduction mode (CCM), the

internal clock initiates a pulse-width modulation

(PWM) cycle. The high-side MOSFET (HS-

reaches the value set by the COMP voltage

side MOSFET (LS-FET) turns on and remain on

until the next clock cycle begins. The MP8714

repeats this operation in every clock cycle to

regulate the output voltage.

(500kHz switching frequency) within 95% of

one PWM period, the HS-FET is forced off.

AAM Control Operation

In light-load condition, the MP8714 works in

advanced asynchronous modulation (AAM)

voltage when the input and output voltages are

represents peak inductor current information.

clock is blocked, so the MP8714 skips some

pulses and achieves light-load power save.

Refer to the related application note (AN032)

for more detail.

The light-load feature in this device is optimized

for 12V input applications.

Figure 2: Simplified AAM Control Logic

DCM Control Operation

the MP8714 enters discontinuous conduction

mode (DCM) (see Figure 3). In this mode, the

internal clock initiates the PWM cycle. The HS-

of dead time, the LS-FET turns on and remain

on until the inductor current value decreases to

zero. The MP8714 repeats this same operation

in every clock cycle to regulate the output

voltage.

Figure 3: DCM Control Operation

VCC Regulator

A 5V internal regulator powers most of the

internal circuitries. This regulator takes the VIN

input and operates in the full VIN range. When

VIN is greater than 5.0V, the output of the

regulator is in full regulation. When VIN is lower

than 5.0V, the output voltage decreases and

follows the input voltage. A 0.47μF ceramic

capacitor is required for decoupling purposes.

Error Amplifier (EA)

The error amplifier compares the FB voltage

with the internal 0.6V reference (REF) and

outputs a COMP voltage, which is used to

control the power MOSFET current. The

optimized

internal

compensation