MP86933

– 16V, INTELLI-PHASE SOLUTION IN TQFN 3X3 PACKAGE

MP86933 Rev.1.2

www.MonolithicPower.com

11

5/26/2021

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Current Sense Output (CS)

CS is a bidirectional current source proportional

to the inductor current. The current sensing gain

is 10μA/A. A resistor is used to program the

voltage gain proportional to the inductor current

if needed.

The CS output has two states (see Table 1). In

standby mode, the CS circuit is disabled and

needs 20µs to wake up and enter active mode if

needed.

Table 1: CS Output States

PWM

SYNC

CS

PWM

High

Active

PWM

High

Active

PWM

Low

Active

x

Hi-Z (or middle)

Standby

The CS voltage range of 0.7V to 2.1V is required

to obtain an accurate CS current output up to

+500μA/-200μA (i.e.: +50A/-12A). Generally,

there is a resistor (RCS) connected from CS to an

external voltage which is capable of sinking

small currents to provide enough of a voltage

level to meet the required operating voltage

range.

Figure 2 shows the typical circuit diagram of the

CS connection to achieve a differential voltage

source reflected in the inductor current.

VCS

SW

PWM

Intelli-Phase

PWM

IL

Vin

VIN

GND

CS

RCS

VCM

ICS

Figure 2: Typical Circuit Diagram for CS

Connection

To keep VCS within the operating range, design

RCS with Equation (1) and Equation (2):

V

V

R

I

V

CM

CS

CS

1

.

2

7

.

0









(1)

CS

L

CS

I

I

G



(2)

Where VCM is the reference voltage connected to

RCS.

VCM can be from a voltage divider from 3.3V (i.e.:

VCC) (see Figure 3).

Make RCS much larger than R1 parallel to R2 to

minimize VCM variation over ICS.

VCM

VCC

R1

R2

VCS

SW

PWM

Intelli-Phase

PWM

Vin

VIN

GND

CS

RCS

ICS

L

DCR

VOUT

COUT

IL

Figure 3: Use VCC to Generate VCM for CS Signal