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L6710

Figure 2. Drivers peak current: High Side (left) and Low Side (right).

CURRENT READING AND OVER CURRENT

issued by the external resistor Rg placed outside the chip between ISENx and PGNDS pins toward the

reading points.

The differential current reading rejects noise and allows to place sensing element in different locations

without affecting the measurement's accuracy. The current reading circuitry reads the current during the

time in which the low-side mosfet is on (OFF Time). During this time, the reaction keeps the pin ISENx

and PGNDS at the same voltage while during the time in which the reading circuitry is off, an internal clamp

keeps these two pins at the same voltage sinking from the ISENx pin the necessary current (Needed if

The proprietary current reading circuit allows a very precise and high bandwidth reading for both positive

and negative current. This circuit reproduces the current flowing through the sensing element using a high

speed Track & Hold transconductance amplifier. In particular, it reads the current during the second half

of the OFF time reducing noise injection into the device due to the mosfet turn-on (See fig. 3). Track time

must be at least 200ns to make proper reading of the delivered current.

This circuit sources a constant 100

µA current from the PGNDS pin: it must be connected through two

equal Rg resistors to the groundside of the sensing element (See Figure 3). The two current reading cir-

cuitry uses this pin as a reference keeping the ISENx pin to this voltage.

The current that flows in the ISENx pin is then given by the following equation:

carried by the relative phase. The current information reproduced internally is represented by the second

term of the previous equation as follow:

CH3 = HGATE1; CH4 = HGATE2

CH3 = LGATE1; CH4 = LGATE2

I

ISEN x

50

µA

R

SEN SE

I

PH AS Ex

⋅

R

g

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

50

µAI

IN FO x

+

=

+

=

I

IN FO x

R

SEN SE

I

PH AS Ex

⋅

R

g

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

=