AS1121-BQFT austriamicrosystems, AS1121-BQFT Datasheet - Page 13

• Manufacturer Part Number: AS1121-BQFT
• Description: IC LED DRIVER 16-CH 30V 32-TQFN
• Manufacturer: austriamicrosystems

Specifications of AS1121-BQFT

• Constant Current: Yes
• Internal Driver: Yes
• Type - Primary: Backlight, General Purpose
• Type - Secondary: Color
• Mounting Type: *
• Topology: PWM
• Number Of Outputs: 16
• Voltage - Supply: 3.1 V ~ 3.6 V
• Voltage - Output: 1.5 V ~ 30 V
• Package / Case: *
• Operating Temperature: -40°C ~ 85°C
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Frequency: -
• Other names: AS1121-BQFTTR

AS1121
Datasheet - D e t a i l e d D e s c r i p t i o n
Greyscale PWM Operation
The falling edge of the OEN signal initiates a greyscale PWM cycle. The first GSCLK pulse after the falling edge of OEN increments the grey-
scale counter by one and switches on any OUTn whose greyscale value does not equal zero. Each subsequent rising edge of GSCLK incre-
ments the greyscale counter by one.
The AS1121 compares the greyscale value of each OUTn channel with the greyscale counter value. All OUTn whose greyscale values equal the
counter values are switched off. A OEN = 1 signal after 4096 GSCLK pulses resets the greyscale counter to zero and completes a greyscale
PWM cycle
Figure 10. Greyscale PWM Cycle Timing Diagram
Output Delay
To minimize the ripple on the inrush current, the outputs are delayed and are not switching at the same time. The 16 channels of the AS1121 are
combined in groups of 4. The channels within the groups OUT0:OUT3, OUT4:OUT7, OUT8:OUT11, OUT12:OUT15 are switching at the same
time. Between the 4 groups a delay of t
17).
To increase the EMI performance the rising and falling edges of the OUTn signals are symmetrical (t
factory set and can be changed on request. For further information and requests, please contact us
www.austriamicrosystems.com/LED-Driver-ICs
OUT12:OUT15
Current
OUT8:OUT11
Current
OUT4:OUT7
Current
OUT0:OUT3
Current
GSCLK
OEN
XERR
(see Figure
all LED’s ON
10).
d
all LED’s OFF
= 25ns (typ.) is implemented. On request this delay can be turned off
t
t
t
PD2
PD2
PD2
t
PD2
+2xt
+3xt
+t
d
d
d
t
WH1
1
Revision 1.00
t
PD1
2
t
t
WL1
W1
Greyscale PWM
Cycle n
3
t
PD2
mailto:[e-mail].
R
= t
4096
F
= 25ns). The rise- and fall-times are
t
H4
(see Ordering Information on page
t
PD2
t
WH3
Greyscale
Cycle n+1
PWM
t
SU4
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