STP1612PW05 datasheet(21/35 Pages) STMICROELECTRONICS

Il numero della parte	STP1612PW05

Spiegazioni elettronici	16-channel LED driver with 16-bit PWM, 8-bit gain and full LED error detection

PDF	35 Pages

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Produttore elettronici	STMICROELECTRONICS [STMicroelectronics]

Homepage	http://www.st.com

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21 / 35 page

STP1612PW05

Setting output current

Doc ID 15819 Rev 4

21/35

Setting output current

The output current (IOUT) is set by an external resistor, Rext.

It is calculated from the equation:

VR-EXT = 1.24 x G; IOUT = (VR-EXT/Rext) x 560

Whereas Rext is the resistance of the external resistor connected to R-EXT terminal

and VR-EXT is its voltage. G is the digital current gain, which is set by the bit9 – bit2 of the

configuration register. The default value of G is 1. For your information, the output current is

about 20 mA when Rext = 34.70 kΩ and 10 mA when Rext = 69.6 kΩ if G is set to

default value 1. The formula and setting for G are described in next section.

Figure 12.

Rext vs output current

Table 15.

Rext vs output current (1)

TA = 25 °C, Vdd = 3.3 V; 5.0 V, VLed = 3.0 V, Vdrop = 1.5 V, HC = 0101011 (default)

Iout (mA)

Rext (k

Ω)

238.2

142.2

69.6

34.70

22.94

13.72

11.40

8.63

100

125

150

175

200

225

250

275

Iout (mA)

STP1612PW05 Scheda tecnica(PDF) 21 Page - STMicroelectronics