AN4243

Designing an application with the L6230

Doc ID 024199 Rev 1

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avoided. Should a layer change be necessary, multiple and large via holes have to be used.

A wide GND copper area can be used to improve power dissipation for the device.

Figure 6 shows two typical situations that must be avoided. An important consideration

about the location of the bulk capacitor is the ability to absorb the inductive energy from the

load, without allowing the supply voltage to exceed the maximum rating. The diode shown in

Figure 6 prevents the recirculation current from reaching the capacitors and results in a high

voltage on the IC pins that can damage the device.

Having a switch or a power connection that can disconnect the capacitors from the IC, while

there is still current in the motor, also results in a high-voltage transient since there is no

capacitance to absorb the recirculation current.

Figure 6.

Layout suggestions

2.5

Sensing resistor

Each motor winding current flows through the sensing resistors, causing a voltage drop that

is used to control the peak value of the load current. Two issues must be taken into account

The sensing resistor dissipates energy and provides dangerous negative voltages on the

SENSE pins during the current recirculation. For this reason, the resistance of this

component should be kept low.

A good compromise is to calculate the sensing resistor value so that the voltage drop,

Equation 8

GND

GND

GND

GND

SENSE

SENSE

R5

C1

C8

C2

L6230

DO NOT connect the logic GND here

Voltage drop due to current in sense path

can disturb logic GND

DO NOT put a diode here!

Recirculating current cannot flow into the

bulk capacitor and causes a high voltage

spike that can damage the IC

SENSE3

AM16568v1

R

SENSE

0.5V

I

peak

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=