MP86952

– 70A INTELLI-PHASE™ SOLUTION WITH BUILT-IN MOSFETS AND DRIVERS

MP86952 Rev. 1.0

MonolithicPower.com

8

5/13/2021

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OPERATION

The MP86952 is a 16V, 70A, monolithic, half-

bridge Intelli-Phase

™ solution with integrated

power MOSFETs and drivers. It is ideal for

multi-phase buck regulator applications.

An external 3.3V supply is required to supply

both the VDD and VDRV pins. Once the EN,

VDD, and VDRV pins transition from low to

high, the part starts up.

Pulse-Width Modulation (PWM)

The pulse-width modulation (PWM) input can

operate as a tri-state input. If the PWM input

signal is within the tri-state threshold window

(tHT to tLT) for 50ns, then the high-side MOSFET

(HS-FET) turns off and the low-side MOSFET

(LS-FET) enters diode emulation mode. The

LS-FET remains in diode emulation mode until

zero-current

detection

(ZCD).

The

tri-state

PWM input can come from a forced middle-

voltage PWM signal, or can be made by floating

the PWM input so that the internal current

source charges the signal to a middle voltage.

Figure 2 shows the propagation delay definition

from PWM to the SW node.

tRISING

tFALLING

tLT

tTH

tHT

tTL

SW

PWM

Hi-Z

Hi-Z

Figure 2: PWM Timing Diagram

Diode Emulation Mode

In diode emulation mode, PWM is low or in a tri-

state input. If the inductor current (IL) is positive,

then the LS-FET turns on. If IL is negative or

crosses the ZCD threshold, then the LS-FET

turns off. Diode emulation mode can be

enabled by driving the PWM pin to a middle

state or floating PWM.

Current Sense (CS)

The MP86952’s current sense (CS) is a

bidirectional current source proportional to IL.

The current-sense gain (GCS) is 5μA/A. A

resistor can be used to adjust the voltage gain

to be proportional to IL.

The IOUT pin has two output states (see Table

1). If EN is low (disabled), then the current-

sense circuit is disabled and IOUT is in a high-

impedance (Hi-Z) state.

Table 1: IOUT Output States

PWM

EN

IOUT

Enabled

High

Active

Disabled

Low

Hi-Z

IOUT requires a 0.7V to 2.1V voltage range to

achieve an accurate current output of up to

+350

μA/-200μA (+70A/-40A). A resistor (RIOUT)

from IOUT to an external voltage is typically

used to sink small currents and provide the

0.7V to 2.1V voltage level to meet the IOUT

operating voltage. The proper reference voltage

(VCM) connected to RIOUT can be calculated with

Equation (1):

IOUT

IOUT

CM

0.7V

I

R

V

2.1V









(1)

The output current (IIOUT) can be calculated with

Equation (2):

IOUT

SW

IOUT

I

I

G



(2)

The Intelli-PhaseTM current-sense output is