ISL78171 Datasheet, PDF (20/29 Pages) Intersil Corporation – 6-Channel, 50mA Automotive LED Driver with Ultra-high Dimming Ratio and Phase Shift Control

ISL78171
TABLE 3A. ISL78171 REGISTER LISTING
ADDRESS
REGISTER
BIT 7 BIT 6
BIT 5
BIT 4
BIT 3
BIT 2
BIT 1
DEFAULT SMBUS/I²C
BIT 0 VALUE PROTOCOL
0x00
PWM Brightness
Control Register
BRT7
BRT6
BRT5
BRT4
BRT3
BRT2
BRT1
BRT0
0xFF Read and
Write
0x01
Device Control
Register
Reserved Reserved Reserved Reserved Reserved PWM_MD PWM_SEL BL_CTL
0x00 Read and
Write
0x02
Fault/Status Register Reserved Reserved 2_CH_SD 1_CH_SD BL_STAT OV_CURR THRM_SHDN FAULT
0x00 Read Only
Note 11)
0x03
Identification
Register
LED
Panel
MFG3
MFG2
MFG1
MFG0
REV2
REV1
REV0 0xC8 Read Only
0x07
DC Brightness Control BRTDC7 BRTDC6 BRTDC5 BRTDC4 BRTDC3 BRTDC2
Register
BRTDC1
BRTDC0
0xFF
Read and
Write
0x08
Configuration Reserved Reserved Reserved BstSlew BstSlew FSW
Reserved
VSC
0x1F Read and
Register
Rate1 Rate0
Write
0x09
Output Channel Reserved Reserved CH5
CH4
CH3
CH2
CH1
CH0 0x3F Read and
Register
Write
0x0A
Phase Shift Deg
Equal Phase
Phase Shift6
Phase
Shift5
Phase
Shift4
Phase
Shift3
Phase
Shift2
Phase
Shift1
Phase
Shift0
0x00 Read and
Write
0x7F
Note 10)
Secondary Boost
Oscillator
Enable Must be 0 Must be 0 Must be 0 Must be 0 Must be 0 Must be 0 Must be 0 0x00 Read and
Write
TABLE 3B. DATA BIT DESCRIPTIONS
ADDRESS
REGISTER
DATA BIT DESCRIPTIONS
0x00
PWM Brightness Control
Register
BRT[7..0] = 256 steps of DPWM duty cycle brightness control
0x01 Device Control Register
PWM_MD, PWM_SEL: select the dimming method - see Table 4 for more details. Default = 00
BL_CTL = BL On/Off (1 = On, 0 = Off), default = 0
0x02 Fault/Status Register
2_CH_SD = Two LED output channels are shutdown (1 = shutdown, 0 = OK)
1_CH_SD = One LED output channel is shutdown (1 = shutdown, 0 = OK)
BL_STAT = BL status (1 = BL On, 0 = BL Off)
OV_CURR = Input overcurrent (1 = Overcurrent condition, 0 = Current OK)
THRM_SHDN = Thermal Shutdown (1 = Thermal fault, 0 = Thermal OK)
FAULT = Fault occurred (Logic “OR” of all of the fault conditions)
0x03 Identification Register
LED PANEL = 1
MFG[3..0] = Manufacturer ID (16 vendors available. Intersil is vendor ID 9)
REV[2..0] = Silicon rev (Rev 0 through Rev 7 allowed for silicon spins)
0x07 DC Brightness Control Register BRTDC[7..0] = 256 steps of DC brightness control
0x08 Configuration Register
BstSlewRate[1..0] = Controls strength of FET driver. 00 - 25% drive strength, 01 - 50% drive strength,
10 - 75% drive strength, 11 - 100% drive strength.
f_SW = Switching frequencies selection, f_SW = 0 = 1.2MHz. f_SW = 1 = 600kHz
VSC[0] = Short circuit thresholds selection, 0 = disabled, 1 = 7.5V minimum
0x09
Output Channel Mask/Fault
Readout Register
CH[5..0] = Output Channel Read and Write. In Write, 1 = Channel Enabled, 0 = Channel Disabled. In
Read, 1 = Channel OK, 0 = Channel Not OK/Channel disabled
0x0A Phase Shift Degree
EqualPhase = Controls phase shift mode - When 1, phase shift is 360/N (where N is the number of
channels enabled). When 0, phase shift is defined by PhaseShift<6:0>.
PS[6..0] = 7-bit Phase shift setting - phase shift between each channel is
PhaseShift<6:0>/(255*PWMFreq). In direct PWM modes, phase shift between each channel is
PhaseShift<6:0>/12.8MHz.
0x7F Secondary Boost Oscillator
Note 10)
Enable = 1: Use the secondary boost oscillator 800kHz OR Enable = 0, use the primary
600kHz/1.2MHz oscillator.
10. Bit 7 of an additional register 0x7F that allows selecting an override boost frequency of 800kHz. This is done by writing 0x80 to register 0x7F. The
default value for register 0x7F is 0x00 when either 600kHz or 1.2MHz boost frequency is being used. Please ensure that the rest of the bits 0-6 in
register 0xF should remain at 0 at all times, failing to do so will adversely affect the PWM performance of the LED.
11. FAULT is a Read & Write bit.
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FN8602.0
June 15, 2015