HV9911 Ver la hoja de datos (PDF) - Supertex Inc

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componentes Descripción

Fabricante

HV9911

Switch-mode LED Driver IC with High Current Accuracy

Supertex Inc 

HV9911

the internal amplifier controls the output current. When the

PWMD signal goes low, the output of the transconductance

amplifier is disconnected from the compensation network.

Thus, the integrating capacitor maintains the voltage across

it. The GATE is disabled, so the converter stops switching

and the FAULT pin goes low, turning off the disconnect

switch.

discontinuous, and a very large output capacitor is required

to reduce the ripple in the LED current. Thus, this capacitor

will have a significant impact on the PWM dimming response.

By turning off the disconnect switch when PWMD goes low,

the output capacitor is prevented from being discharged,

and thus the PWM dimming response of the boost converter

improves dramatically.

The output capacitor of the converter determines the

PWM dimming response of the converter, since it has to

get charged and discharged whenever the PWMD signal

goes high or low. In the case of a buck converter, since the

inductor current is continuous, a very small capacitor is used

across the LEDs. This minimizes the effect of the capacitor

on the PWM dimming response of the converter. However,

in the case of a boost converter, the output current is

Note that disconnecting the capacitor might cause a sudden

spike in the capacitor voltage as the energy in the inductor

is dumped into the capacitor. This might trigger the OVP

comparator if the OVP point is set too close to the maximum

operating voltage. Thus, either the capacitor has to sized

slightly larger or the OVP set point has to be increased.

16-LEAD SO PACKAGE (NG) (NARROW BODY)

0.3895 ± 0.0045

(9.8935 ± 0.1145)

0.156 ± 0.002

(3.962 ± 0.051)

0.2335 ± 0.0105

(5.931 ± 0.267)

0.500

(12.700)

TYP.

0.065 ± 0.004

(1.651 ± 0.102)

0.020 ± 0.002

(0.508 ± 0.0508)

0.350

(8.890)

TYP.

0.193 ± 0.012

(4.9022 ± 0.3048)

0.0255 ± 0.0005

(0.6475 ± 0.0125)

0.009 ± 0.002

(0.216 ± 0.038)

7° (4 PLCS)

45°

0.013 ± 0.004

(0.3302 ± 0.1016)

0.059 ± 0.002

(1.499 ± 0.051)

7° (4 PLCS)

0° - 8 °

0.050 TYP.

(1.270)

0.0165 ± 0.0035

(0.4191 ± 0.0889)

0.006 ± 0.002

(0.1524 ± 0.0508)

0.033 ± 0.017

(0.8382 ± 0.4318)

0.0275 ± 0.0025

(0.6985 ± 0.0635)

Measurement Legend = Dimensions in Inches

(Dimensions in Millimeters)

Doc.# DSFP - HV9911

NR011206

9

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