AN1762 datasheet(22/53 Pages) STMICROELECTRONICS

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AN1762 APPLICATION NOTE

22/53

Figure 22. Output Current Detection Threshold versus RCL Value (L6206 ONLY)

The Over Current Detection threshold can also be adjusted through an external reference voltage, as shown in

Figure 23. The external reference voltage source should be able to sink current (about 300 µA maximum). More-

over, if supply voltage is provided to the L6206 before VEXT, and its EN pins are at a high logic level, the device

starts working with minimum OCD threshold (actually the capacitor placed at the bottom of RCL allows a short

start-up time with higher OCD threshold). VEXT can also be obtained through a PWM output of a µC, adding a

series resistor to obtain a low-pass filter.

The OCD threshold (ISOVER) follows the equation:

ISOVER =

±10%,

at -25 °C < Tj < 125 °C

if 0.5 A < ISOVER < 4.5 A

Figure 23. Adjusting the OCD Threshold through an external reference voltage (L6206 ONLY)

10k

15k

20k

25k

30k

35k

40k

0.5

1.5

2.5

3.5

CL [Ω ]

4.5

SO VER

[A]

18416.7 1.2V

Ve xt

–

()

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

RCL

PROGCLA

L6206

Vext = 0 ÷ 1.2 V

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