HV9903 Ver la hoja de datos (PDF) - Supertex Inc
Número de pieza
componentes Descripción
Fabricante
HV9903 Datasheet PDF : 12 Pages
| |||
HHVV99990033
PWM Dimming via RSET
D
COUT
ILED ( avg )
L
VDD
HV9903
1 SW
VDD 6
2 GND SHDN 5
CDD
Shutdown
3 LED
RSET 4
RSET
PWM
(1
D)
22.5V
RSET
The logic signal must have a low output impedance
relative to RSET and be capable of going to within a
few millivolts of ground. The following modification
provides higher immunity to the logic low voltage level
(VLO). It also minimizes the effect of voltage
differences between the HV9903’s ground and the
PWM signal source’s ground.
PWM Dimming via RSET
L
D
COUT
HV9903
1 SW
VDD 6
2 GND SHDN 5
3 LED
RSET 4
RPWM
RSET
VHI
100mV
1
VDD
CDD
Shutdown
RPWM
RSET
PWM
( ) ILED (avg)
225 1 D
100mV 100mV VLO
RSET
RPWM
DC dimming may be implemented in discrete steps
using logic signals, as shown below.
Multi-level Logic Dimming
L
D
COUT
HV9903
1 SW
VDD 6
2 GND SHDN 5
3 LED
RSET 4
VDD
CDD
Shutdown
RSET
Dual-cell Alkaline Operation
The HV9903 LED driver may be used in 2-cell alkaline
battery applications (1.8V min) by powering the power
stage directly from the batteries, while powering the
HV9903 from an available 3.3V supply. Supplying the
power stage directly from the batteries reduces the
load on the 3.3V supply, which in turn increases
overall efficiency and keeps components small. The
same dimming techniques used in the single-supply
application may be used in this dual-supply
application.
2-cell Alkaline Circuit
L
D
1.8–3.0V
COUT
CIN
HV9903
1 SW
VDD 6
2 GND SHDN 5
3 LED
RSET 4
2.6–4.6V
Shutdown
Fault
RSET
VDD
CDD
8
Share Link: 