ISL97673IRZ-TK Intersil, ISL97673IRZ-TK Datasheet - Page 13

• Manufacturer Part Number: ISL97673IRZ-TK
• Description: IC LED DVR PWM CTRL 6CH 20QFN
• Manufacturer: Intersil

Specifications of ISL97673IRZ-TK

• Topology: PWM, Step-Up (Boost)
• Number Of Outputs: 6
• Internal Driver: Yes
• Type - Primary: Automotive, Backlight
• Type - Secondary: RGB, White LED
• Frequency: 600kHz, 1.2MHz
• Voltage - Supply: 4.5 V ~ 26.5 V
• Voltage - Output: *
• Mounting Type: Surface Mount
• Package / Case: 20-VFQFN Exposed Pad
• Operating Temperature: -40°C ~ 85°C
• Current - Output / Channel: 40mA
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

Method 2 (External applied PWM)
To use this mode users need to set Register 0x01 to 0x03
The average LED current of each channel can also be
controlled by an external PWM signal as Equation 8:
PWM Dimming Frequency Adjustment
(Applicable to SMBus/I
and DPST Modes)
Except for the external PWM dimming mode, the
dimming frequencies of any other modes are set by an
external resistor at the FPWM pin as Equation 9:
where F
and R
The PWM dimming frequency can be set or applied up to
30kHz with duty cycle from 0.4% to 100%.
PHASE SHIFT CONTROL
The ISL97673 is capable of delaying the phase of each
current source to minimize load transients. By default,
phase shifting is disabled as shown in Figure 20 where
the channels PWM currents are switching uniformly. The
duty cycles can be controlled by the data in PWM
Brightness Control Register via the SMBus/I
an external PWM signal with the frequency set by the
RFPWM, or by an external PWM signal with the frequency
set by the incoming signal.
I
F
FIGURE 20. NO DELAY (DEFAULT PHASE SHIFT
LILED ave
PWM
ILED0
ILED1
ILED2
ILED3
ILED4
ILED5
(
FPWM
=
PWM
6.66
----------------------- -
RFPWM
)
=
is the setting resistor.
×10
DISABLED)
is the desirable PWM dimming frequency
I
LED
t
ON
7
t
×
FPWM
PWM
t
OFF
13
2
C controlled PWM
2
C interface,
(EQ. 8)
(EQ. 9)
ISL97673
FIGURE 21. 6 EQUAL PHASE CHANNELS PHASE SHIFT
FIGURE 22. 4 EQUAL PHASE CHANNELS PHASE SHIFT
When EqualPhase = 1, the phase shift evenly spreads
the channels switching across the PWM cycle, depending
on how many channels are enabled, as shown in
Figures 21 and 22. Equal phase means there are fixed
delays between channels and such delay can be
calculated as Equations 10 and 11:
where (255/N) is rounded down to the nearest integer.
For example, if N = 6, (255/N) = 42, that leads to:
t
t
where t
of LED channels. The ISL97673 will detect the numbers
of operating channels automatically.
t
t
D1
D2
D1
D2
PWMI
ILED1
ILED2
ILED3
ILED4
ILED1
PWMI
ILED0
ILED1
ILED2
ILED3
ILED4
ILED5
ILED0
= t
= t
=
=
t
D1
t
------------------ - x
t
------------------ - x 255
FPWM
FPWM
60%
= Fixed Delay with Integer only while the decimal value will be discarded (eg. 63.75=63)
FPWM
FPWM
255
255
FPWM
60%
t
D1
t
PWMin
40%
t
D1
ILLUSTRATION
ILLUSTRATION
x 42/255
x 45/255
40%
60%
⎛
⎝
⎛
⎝
is the sum of t
t
255
--------- -
D1
N
t
D1
t
⎞
⎠
ON
–
t
t
60%
D1
D1
(t
t
PWMout
(
FPWM
N 1
t
D1
t
–
)
40%
D1
)
t
t
D2
OFF
⎛
⎝
40%
t
255
--------- -
D2
N
ON
⎞
⎠
⎞
⎠
t
and t
ON
t
FPWM
OFF
. N is the number
t
OFF
June 24, 2010
(EQ. 10)
(EQ. 11)
FN7633.0