L6710

12/34

Since the current is read in differential mode, also negative current information is kept; this allow the de-

vice to check for dangerous returning current between the two phases assuring the complete equalization

between the phase's currents. From the current information of each phase, information about the total cur-

current carried by the two phases.

The transconductance resistor Rg can be designed in order to have current information of 25

µA per phase

µA).

placed at 1/2 of the total delivered maximum current, results:

Since the device senses the output current across the low-side mosfets (or across a sense resistors in

series with them) the device limits the bottom of the inductor current triangular waveform: an over current

µA).

Introducing now the maximum ON time dependence with the delivered current (where T is the switching

This linear dependence has a value at zero load of 0.80·T and at maximum current of 0.40·T typical and

results in two different behaviors of the device:

Figure 3. Current reading timing (left) and circuit (right)

I

OC Px

35

µARg

⋅

R

SEN S E

---------------------------

Rg

I

OC Px

R

SEN SE

⋅

35

µA

------------------------------------------

=

=

T

ON,MAX

0.80

I

FB

–

5.73k

⋅

() T0.80

R

SEN S E

Rg

---------------------- I

OUT

5.73k

⋅⋅

–





T =

T

0.80 T I

FB

0

µA

=

⋅

=

T

0.40 T I

FB

70

µA

=

⋅

=











⋅

=

⋅

=

Rg

50

µA

Rg

LGATE1

ISEN1

PGNDS

Rg

50

µA

100

µA

Rg

ISEN2

TOTAL

CURRENT

Track & Hold