LM3535 Datasheet, PDF (15/34 Pages) National Semiconductor (TI) – Multi-Display LED Driver with Ambient Light Sensing and Dynamic Backlight Control Compatibility

LM3535
www.ti.com
SNVS598A – AUGUST 2010 – REVISED MAY 2013
• 62A: Assign D62 diode to BankA. Writing a '0' assigns D62 to BankB (default) and a '1' assigns D62 to
BankA.
• ALS-ENA: Enable ALS on BankA. Writing a '1' enables ALS control of diode current and a '0' (default) forces
the BankA current to the value stored in the BankA brightness register. The ALS-EN bit must be set to a '1'
for the ALS block to control the BankA brightness.
• ALS-ENB: Enable ALS on BankB. Writing a '1' enables ALS control of diode current and a '0' (default) forces
the BankB current to the value stored in the BankB brightness register. The ALS-EN bit must be set to a '1'
for the ALS block to control the BankB brightness. The ALS function for BankB is different than bankA in that
the ALS will only enable and disable the BankB diodes depending on the ALS zone chosen by the user.
BankA utilizes the 5 different zone brightness registers (Addresses 0x70 to 0x74).
• ALS-EN: Enables ALS monitoring. Writing a '1' enables the ALS monitoring circuitry and a '0' disables it. This
feature can be enabled without having the current sinks or charge pump active. The ALS value is updated in
register 0x40 (ALS Zone Register)
• ALSF: ALS Interrupt Enable. Writing a '1' sets the D1B/INT pin to the ALS interrupt pin and writing a '0'
(default) sets the pin to a BankB current sink.
Options Register
Register Address: 0x30
GT1
GT0
RD2
RD1
RD0
RU2
RU1
RU0
bit7
bit6
bit5
bit4
bit3
bit2
bit1
bit0
Figure 32. Options Register
Internal Hex Address: 0x30
• RD0-RD2: Diode Current Ramp Down Step Time. : ‘000’ = 6µs, ‘001’ = 0.77ms, ‘010’ = 1.5ms, ‘011’ = 3ms,
‘100’ = 6ms, ‘101’ = 12ms, ‘110’ = 25ms, ‘111’ = 50ms
• RU0-RU2: Diode Current Ramp Up Step Time. : ‘000’ = 6µs, ‘001’ = 0.77ms, ‘010’ = 1.5ms, ‘011’ = 3ms, ‘100’
= 6ms, ‘101’ = 12ms, ‘110’ = 25ms, ‘111’ = 50ms
• GT0-GT1: Gain Transition Filter. The value stored in this register determines the filter time used to make a
gain transition in the event of an input line step. Filter Times = ‘00’ = 3-6ms, ‘01’ = 0.8-1.5ms, ‘10’ = 20µs, On
LM3535-2ALS, '11' = 1µs, On LM3535, ‘11’ = DO NOT USE
The Ramp-Up and Ramp-Down times follow the following equations: T_RAMP = (N_Start - N_Target) × Ramp-Step Time
DxA Brightness Control
MSB
Register Address: 0xA0
LSB
1
DxA6 DxA5 DxA4 DxA3 DxA2 DxA1 DxA0
bit7
bit6
bit5
bit4
bit3
bit2
bit1
bit0
MSB
1
bit7
DxB Brightness Control
Register Address: 0xB0
LSB
1
ALSZT2 ALSZT1 ALSZT0 DxB2 DxB1 DxB0
bit6
bit5
bit4
bit3
bit2
bit1
bit0
DxC Brightness Control
MSB
Register Address: 0xC0
LSB
1
1
1
1
1
D1C2 D1C1 D1C0
bit7
bit6
bit5
bit4
bit3
bit2
bit1
bit0
Figure 33. Brightness Control Register Description
Internal Hex Address: 0xA0 (GroupA), 0xB0 (GroupB), 0xC0 (GroupC)
Copyright © 2010–2013, Texas Instruments Incorporated
Product Folder Links: LM3535
Submit Documentation Feedback
15