Datasheet

ManualsBrandsMAXIM INTEGRATED ManualsPMICsPMIC - lighting/front end device controller CCFL controller TSSOP 28 Surface-mount

General Description

The DS3882 is a dual-channel cold-cathode fluorescent

lamp (CCFL) controller for automotive applications that

provides up to 300:1 dimming. It is ideal for driving

CCFLs used to backlight liquid crystal displays (LCDs)

in navigation and infotainment applications and for dri-

ving CCFLs used to backlight instrument clusters. The

DS3882 is also appropriate for use in marine and avia-

tion applications.

The DS3882 features EMI suppression functionality and

provides a lamp current overdrive mode for rapid lamp

heating in cold weather conditions. The DS3882 sup-

ports configurations of 1 or 2 lamps with fully indepen-

dent lamp control and minimal external components.

Multiple DS3882 controllers can be cascaded to sup-

port applications requiring more than 2 lamps. Control of

the DS3882, after initial programming setup, can be

completely achieved through I

C software communica-

tion. Many DS3882 functions are also pin-controllable if

software control is not desired.

Applications

Automotive LCDs

Instrument Clusters

Marine and Aviation LCDs

Features

♦ Dual-Channel CCFL Controllers for Backlighting

LCD Panels and Instrument Clusters in

Automotive Navigation/Infotainment Applications

♦ Minimal External Components Required

♦ I

C Interface

♦ Per-Channel Lamp-Fault Monitoring for Lamp-

Open, Lamp-Overcurrent, Failure to Strike, and

Overvoltage Conditions

♦ Status Register Reports Fault Conditions

♦ Accurate (±5%) Independent On-Board Oscillators

for Lamp Frequency (40kHz to 100kHz) and DPWM

Burst-Dimming Frequency (22.5Hz to 440Hz)

♦ Lamp and DPWM Frequencies can be

Synchronized with External Sources to Reduce

Visual LCD Artifacts in Video Applications

♦ Optional Spread-Spectrum Lamp Clock Reduces

EMI

♦ Lamp Frequency can be Stepped Up or Down to

Move EMI Spurs Out of Band

♦ Lamp Current Overdrive Mode with Automatic

Turn-Off Quickly Warms Lamp in Cold

Temperatures

♦ Analog and Digital Brightness Control

♦ 300:1 Dimming Range Possible Using the Digital

Brightness Control Option

♦ Programmable Soft-Start Minimizes Audible

Transformer Noise

♦ On-Board Nonvolatile (NV) Memory Allows Device

Customization

♦ 8-Byte NV User Memory for Storage of Serial

Numbers and Date Codes

♦ Low-Power Standby Mode

♦ 4.75V to 5.25V Single-Supply Operation

♦ Temperature Range: -40°C to +105°C

♦ 28-Pin TSSOP Package

DS3882

Dual-Channel Automotive CCFL Controller

______________________________________________

Maxim Integrated Products

OVD2

LCM2

GB2

GA2SCL

SDA

FAULT

TOP VIEW

PDN

LCOBRIGHT

LOSC

218 GNDPSYNC

209 STEPPOSC

1910 N.C.A1

1811 OVD1GND_S

1712 LCM1SVML

1613 GB1SVMH

1514 GA1V

LSYNC

TSSOP

DS3882

Pin Configuration

19-5666; Rev 2; 12/10

For pricing, delivery, and ordering information, please contact Maxim Direct at 1-888-629-4642,

or visit Maxim’s website at www.maxim-ic.com.

Denotes a lead(Pb)-free/RoHS-compliant package.

T&R = Tape and reel.

Ordering Information

Typical Operating Circuit appears at end of data sheet.

PART TEMP RANGE PIN-PACKAGE

DS3882E+C -40°C to +105°C 28 TSSOP

DS3882E+T&R/C -40°C to +105°C 28 TSSOP

Summary of content (31 pages)

PAGE 1
9-5666; Rev 2; 12/10 Dual-Channel Automotive CCFL Controller Features The DS3882 is a dual-channel cold-cathode fluorescent lamp (CCFL) controller for automotive applications that provides up to 300:1 dimming. It is ideal for driving CCFLs used to backlight liquid crystal displays (LCDs) in navigation and infotainment applications and for driving CCFLs used to backlight instrument clusters. The DS3882 is also appropriate for use in marine and aviation applications.
PAGE 2
DS3882 Dual-Channel Automotive CCFL Controller ABSOLUTE MAXIMUM RATINGS Voltage Range on VCC, SDA, and SCL Relative to Ground.....................................-0.5V to +6.0V Voltage Range on Leads Other than VCC, SDA, and SCL ......................-0.5V to (VCC + 0.5V), not to exceed +6.0V Continuous Power Dissipation (TA = +70°C) TSSOP (derate 12.8mW/°C above +70°C) .............1025.6mW Operating Temperature Range .........................-40°C to +105°C EEPROM Programming Temperature Range .........
PAGE 3
Dual-Channel Automotive CCFL Controller (VCC = +4.75V to +5.25V, TA = -40°C to +105°C.) PARAMETER High-Level Output Voltage (GA, GB) SYMBOL VOH1 CONDITIONS IOH1 = -1mA MIN TYP MAX VCC 0.4 UNITS V UVLO Threshold: VCC Rising VUVLOR UVLO Threshold: VCC Falling VUVLOF 4.3 UVLO Hysteresis VUVLOH SVML/H Threshold: Rising VSVMR 2.03 2.08 2.15 V SVML/H Threshold: Falling VSVMF 1.95 2.02 2.07 V 3.7 V V 200 mV LCM and OVD DC Bias Voltage VDCB 1.
PAGE 4
DS3882 Dual-Channel Automotive CCFL Controller I2C AC ELECTRICAL CHARACTERISTICS (See Figure 9) (VCC = +4.75V to +5.25V, TA = -40°C to +105°C, timing referenced to VIL(MAX) and VIH(MIN).) PARAMETER SYMBOL SCL Clock Frequency fSCL Bus Free Time Between Stop and Start Conditions tBUF Hold Time (Repeated) Start Condition tHD:STA CONDITIONS (Note 7) MIN TYP 0 (Note 8) MAX UNITS 400 kHz 1.3 µs 0.6 µs µs Low Period of SCL tLOW 1.3 High Period of SCL tHIGH 0.
PAGE 5
Dual-Channel Automotive CCFL Controller 6.5 6.0 5.5 SVML< 2V 6.7 6.5 6.3 6.1 5.9 4.5 GATE QC = 3.5nC 5.7 fLF:OSC = 64kHz 5.5 4.75 4.80 4.85 4.90 4.95 5.00 5.05 5.10 5.15 5.20 5.25 -40.0 0.2 0 -0.2 -0.4 LAMP FREQUENCY -1.0 -40.0 105 32.5 TEMPERATURE (°C) TEMPERATURE (°C) TYPICAL OPERATION AT 11V TYPICAL OPERATION AT 13V TYPICAL OPERATION AT 16V DS3882 toc04 SUPPLY VOLTAGE (V) 10μs 5.0V GA 10μs 5.0V GA 10μs 5.0V GB 10μs 5.0V GB 10μs 2.00V LCM 10μs 2.00V LCM 10μs 2.00V LCM 10μs 2.
PAGE 6
Typical Operating Characteristics (continued) (VCC = 5.0V, TA = +25°C, unless otherwise noted.) 1ms 5.0V GA 0.5s 5.0V GA 50μs 5.0V GB 1ms 5.0V GB 0.5s 5.0V GB 50μs 2.00V LCM 1ms 2.00V LCM 0.5s 2.00V LCM 50μs 2.00V OVD 1ms 2.00V OVD 0.5s 2.00 OVD 0.2ms 2.00V GA2 DS3882 toc13 DS3882 toc14 AUTORETRY DISABLED STAGGERED BURST DIMMING START 0.2ms 2.00V GA1 0.1s 5.0V GA 0.1s 5.0V GB LAMP OPENED 0.1s 2.00V LCM 0.1s 2.00V OVD 6 DS3882 toc12 50μs 5.
PAGE 7
Dual-Channel Automotive CCFL Controller NAME PINS BY CHANNEL (n) FUNCTION CH 1 CH 2 GAn 15 25 MOSFET A Gate Drive. Connect directly to logic-level mode n-channel MOSFET. Leave open if channel is unused. GBn 16 26 MOSFET B Gate Drive. Connect directly to logic-level mode n-channel MOSFET. Leave open if channel is unused. LCMn 17 27 Lamp Current Monitor Input. Lamp current is monitored by a resistor placed in series with the low-voltage side of the lamp. Leave open if channel is unused.
PAGE 8
Dual-Channel Automotive CCFL Controller DS3882 Pin Description (continued) NAME PIN POSC 9 DPWM Oscillator Resistor Adjust. A resistor to ground on this lead sets the frequency of the DPWM oscillator. This lead can optionally accept a 22.5Hz to 440Hz clock that will become the source timing of the internal DPWM signal. A1 10 Address Select Input. Determines I2C slave address. GND_S 11 I2C Interface Ground Connection. GND_S must be at the same potential as GND.
PAGE 9
Dual-Channel Automotive CCFL Controller PDN UVLO EEPROM LCO SCL A0/A1 GND_S System SYSTEM Enable / ENABLE/ POR POR CONTROL REGISTERS SDA I2C DEVICE CONFIGURATION AND CONTROL PORT VCC [4.75V TO 5.25V] 8 BYTE USER MEMORY I 2C INTERFACE VREF 2.0V SVMH SUPPLY VOLTAGE MONITOR—HIGH 2.
PAGE 10
Dual-Channel Automotive CCFL Controller DS3882 Functional Diagrams (continued) LAMP OUT 300mV LCMn LAMP CURRENT MONITOR CHANNEL ENABLE LAMP OVERCURRENT CHANNEL FAULT LOCE BIT IN CR1.0 DIGITAL CCFL CONTROLLER LAMP STRIKE AND REGULATION 64 LAMP CYCLE INTEGRATOR DIMMING PWM SIGNAL 512 X LAMP FREQUENCY [20.48MHz ~ 51.20MHz] 2.5V OVERVOLTAGE VLRT (1.0V NOMINAL) OVDn OVERVOLTAGE DETECTOR LAMP MAXIMUM VOLTAGE REGULATION LAMP FREQUENCY [40kHz ~ 80kHz] 1.
PAGE 11
Dual-Channel Automotive CCFL Controller Channel Phasing The lamp-frequency MOSFET gate turn-on times are out of phase between the two channels during the burst period. This reduces the inrush current that would result from all lamps switching simultaneously, and hence eases the design requirements for the DC supply. It is important to note that it is the lamp-frequency signals that are phased, not the DPWM (burst) signals.
PAGE 12
DS3882 Dual-Channel Automotive CCFL Controller non-zero PWM code to the BPWM register disables the BRIGHT pin and enables I2C burst dimming control. Setting the 7-bit PWM code to 0000001b causes the DS3882 to operate with the minimum burst duty cycle, while a setting of 1111111b causes a 100% burst duty cycle. For settings between these two codes, the duty cycle varies linearly between the minimum and 100%. Analog Dimming Analog dimming changes the brightness by increasing or decreasing the lamp current.
PAGE 13
Dual-Channel Automotive CCFL Controller 2.0V 0.5V ANALOG BRIGHTNESS BRIGHT PSYNC RESISTOR-SET DIMMING FREQUENCY LSYNC POSC RESISTOR-SET LAMP FREQUENCY 2.0V 0.5V DS3882 LAMP FREQUENCY SOURCE DPWM SOURCE LSYNC POSC RESISTOR-SET DIMMING FREQUENCY LOSC ANALOG BRIGHTNESS 0.5V 2.0V BRIGHT RESISTOR-SET LAMP FREQUENCY DPWM SIGNAL (22.5Hz TO 440Hz) DS3882 LSYNC LAMP FREQUENCY RECEIVER N.C. POSC DPWM RECEIVER N.C. LOSC N.C. LOSC ANALOG BRIGHTNESS 0.
PAGE 14
DS3882 Dual-Channel Automotive CCFL Controller Configuring Systems with Multiple DS3882s gate-driver duty cycle (see Figure 6). This minimizes the possibility of audible transformer noise that could result from current surges in the transformer primary. The soft-start length is fixed at 16 lamp cycles, but the soft-start ramp profile is programmable through the four soft-start profile registers (SSP1/2/3/4) and can be adjusted to match the application.
PAGE 15
Dual-Channel Automotive CCFL Controller Both the lamp and dimming clock frequencies can be set using external resistors. The resistance required for either frequency can be determined using the following formula: ROSC = reaching the strike voltage and could potentially cause numerous other problems. Operating with the transformer voltage at too high of a level can be damaging to the inverter components. Proper use of the SVMs can prevent these problems.
PAGE 16
DS3882 Dual-Channel Automotive CCFL Controller Figure 8 shows a flowchart of how the DS3882 controls and monitors each lamp. The steps are as follows: 1) Supply Check—The lamps do not turn on unless the DS3882 supply voltage is above 4.3V and the voltage at the supply voltage monitors, SVML and SVMH, are respectively above 2.0V and below 2.0V. 2) Strike Lamp—When both the DS3882 and the DC inverter supplies are at acceptable levels, the DS3882 attempts to strike each enabled lamp.
PAGE 17
Dual-Channel Automotive CCFL Controller DS3882 DEVICE AND INVERTER SUPPLIES AT PROPER LEVELS? FAULT STATE [ACTIVATE FAULT OUTPUT] YES SET FAULT_L AND FAULT_RT STATUS BITS RESET FAULT COUNTER AND FAULT OUTPUT YES FAULT WAIT [1024 LAMP CYCLES] NO FAULT COUNTER = 15? NO YES CLEAR FAULT_RT STATUS BIT LAMP OVERCURRENT [INSTANTANEOUS IF ENABLED BY THE LOCE BIT AT CR1.0] AUTORETRY ENABLED? [ARD BIT AT CR1.
PAGE 18
DS3882 Dual-Channel Automotive CCFL Controller EMI Suppression Functionality Lamp Current Overdrive Functionality The DS3882 contains two electromagnetic interference suppression features: spread-spectrum modulation and lamp oscillator frequency stepping. The first is the ability to spread the spectrum of the lamp frequency. By setting either SS0 and/or SS1 in EMIC register, the controller can be configured to dither the lamp frequency by ±1.5%, ±3%, or ±6%.
PAGE 19
Dual-Channel Automotive CCFL Controller BIT R/W POWER-UP DEFAULT NAME FUNCTION Fault Condition—Real Time. A real-time bit that indicates the current operating status of channel 1. 0 = Normal condition 1 = Fault condition 0 R 0 FAULT_RT 1 R 0 FAULT_L 2 R 0 STO_L Lamp Strike Timeout—Latched. A latched bit that is set when the lamp fails to strike. This bit is cleared when read. 3 R 0 OV_L Overvoltage—Latched.
PAGE 20
DS3882 Dual-Channel Automotive CCFL Controller Table 3. Status Register 2 (SR2) [SRAM, E1h] BIT R/W POWER-UP DEFAULT NAME FUNCTION Fault Condition—Real Time. A real-time bit that indicates the current operating status of channel 2. FAULT_RT 0 = Normal condition 1 = Fault condition 0 R 0 1 R 0 FAULT_L 2 R 0 STO_L Lamp Strike Time Out—Latched. A latched bit that is set when the lamp fails to strike. This bit is cleared when read. 3 R 0 OV_L Overvoltage—Latched.
PAGE 21
Dual-Channel Automotive CCFL Controller ADDR FACTORY DEFAULT MSB SSP1 F0h 21h LST1 SSP2 F1h 43h RSVD Lamp Cycles 7 and 8 RSVD Lamp Cycles 5 and 6 SSP3 F2h 65h RSVD Lamp Cycles 11 and 12 RSVD Lamp Cycles 9 and 10 SSP4 F3h 77h RSVD Lamp Cycles 15 and 16 RSVD Lamp Cycles 13 and 14 SSP# DS3882 Table 5a. Soft-Start Protocol Registers (SSPx) [Shadowed-EEPROM, F0h, F1h, F2h, F3h] LSB 7 6 5 4 3 Lamp Cycles 3 and 4 2 LST0 1 0 Lamp Cycles 1 and 2 Table 5b.
PAGE 22
DS3882 Dual-Channel Automotive CCFL Controller Table 6. Control Register 1 (CR1) [Shadowed-EEPROM, F4h] 22 BIT R/W FACTORY DEFAULT NAME 0 R/W 0 LOCE FUNCTION Lamp Overcurrent Enable 0 = Lamp overcurrent detection disabled. 1 = Lamp overcurrent detection enabled. POSC Select. See POSCR0 and POSCR1 control bits in Control Register 2 to select the oscillator range. 0 = POSC input is connected with a resistor to ground to set the frequency of the internal PWM oscillator. 1 = POSC input is a 22.
PAGE 23
Dual-Channel Automotive CCFL Controller BIT R/W DEFAULT NAME 0 R/W 0 UMWP 1 2 R/W R/W 0 0 POSCR0 POSCR1 DS3882 Table 7. Control Register 2 (CR2) [Shadowed-EEPROM, F5h] FUNCTION User Memory Write Protect 0 = Write access blocked. 1 = Write access permitted. DPWM Oscillator Range Select. When using an external source for the dimming clock, these bits must be set to match the external oscillator’s frequency.
PAGE 24
DS3882 Dual-Channel Automotive CCFL Controller Table 8. EMI Control Register (EMIC) [Shadowed-EEPROM, F6h] BIT R/W FACTORY DEFAULT NAME 0 R/W 0 SS0 FUNCTION LAMP OSCILLATOR SPREAD-SPECTRUM MODULATION SELECT 1 R/W 0 SS1 SS1 SS0 SELECTED LAMP FREQUENCY SPREAD 0 0 Spread-Spectrum Disabled 0 1 ±1.5% 1 0 ±3.0% 1 1 ±6.0% 2 R/W 0 SSM Lamp Oscillator Spread-Spectrum Modulation Select 0 = Triangular modulation. 1 = Pseudorandom modulation. 3 ⎯ ⎯ RSVD Reserved.
PAGE 25
Dual-Channel Automotive CCFL Controller BIT R/W FACTORY DEFAULT NAME DS3882 Table 9. Lamp Current Overdrive Control Register (LCOC) [Shadowed-EEPROM, F7h] FUNCTION LAMP CURRENT OVERDRIVE SELECT 0 1 2 3 R/W R/W R/W R/W 0 0 0 0 LCO0 LCO1 LCO2 LCOE LCO2 LCO1 LCO0 SELECTED LAMP CURRENT OVERDRIVE 0 0 0 Nominal Current + 12.50% 0 0 1 Nominal Current + 25.00% 0 1 0 Nominal Current + 37.50% 0 1 1 Nominal Current + 50.00% 1 0 0 Nominal Current + 62.
PAGE 26
DS3882 Dual-Channel Automotive CCFL Controller I2C Definitions The following terminology is commonly used to describe I2C data transfers: Master Device: The master device controls the slave devices on the bus. The master device generates SCL clock pulses, start, and stop conditions. Slave Devices: Slave devices send and receive data at the master’s request. Bus Idle or Not Busy: Time between stop and start conditions when both SDA and SCL are inactive and in their logic-high states.
PAGE 27
Dual-Channel Automotive CCFL Controller I2C Communication Writing a Data Byte to a Slave: The master must generate a start condition, write the slave address byte (R/W = 0), write the memory address, write the byte of data, and generate a stop condition. Remember the master must read the slave’s acknowledgement during all byte write operations. See Figure 11 for more detail.
PAGE 28
DS3882 Dual-Channel Automotive CCFL Controller NOTES COMMUNICATIONS KEY S START A ACK WHITE BOXES INDICATE THE MASTER IS CONTROLLING SDA P STOP N NOT ACK SHADED BOXES INDICATE THE SLAVE IS CONTROLLING SDA SR REPEATED START X X X X X X X X 1) ALL BYTES ARE SENT MOST SIGNIFICANT BIT FIRST. 2) THE FIRST BYTE SENT AFTER A START CONDITION IS ALWAYS THE SLAVE ADDRESS FOLLOWED BY THE READ/WRITE BIT.
PAGE 29
Dual-Channel Automotive CCFL Controller PARAMETER CONDITIONS Turns Ratio (Secondary/Primary) MIN (Notes 1, 2, 3) TYP MAX UNITS 80 kHz 40 Frequency 40 Output Power Output Current 5 Primary DCR Center tap to one end 6 W 8 mA 200 mΩ Secondary DCR 500 Ω Primary Leakage 12 µH Secondary Leakage 185 mH Primary Inductance 70 µH Secondary Inductance 500 mH Secondary Output Voltage DS3882 Table 10.
PAGE 30
Dual-Channel Automotive CCFL Controller DS3882 Typical Operating Circuit VCC R1 DEVICE SUPPLY VOLTAGE (5V ±5%) VCC INVERTER SUPPLY VOLTAGE (VINV) (8V TO 16V) R2 C1 C7 I2C CONFIGURATION AND CONTROL PORT SDA VCC SCL SVMH A0 SVML A1 VCC R3 R4 R5 R6 GND_S R11 FAULT DS3882 CCFL LAMP GA1 C2 C3 R7 GB1 HARDWARE CONTROL LAMP CURRENT OVERDRIVE ENABLE LCO LAMP ON/OFF PDN LAMP BRIGHTNESS BRIGHT STEP LAMP FREQUENCY PSYNC LAMP FREQUENCY INPUT/OUTPUT LSYNC R9 R10 LAMP CURRENT MONI
PAGE 31
Dual-Channel Automotive CCFL Controller PAGES CHANGED REVISION NUMBER REVISION DATE 0 3/06 Initial release — 1 8/07 Updated Table 5b to change bit 7 LST[1:0] at 1:1 from 131,072 lamp frequency cycles to reserved 21 12/10 Updated the Ordering Information table part numbers; added the continuous power dissipation numbers for a single-layer board and the lead and soldering temperature information to the Absolute Maximum Ratings section; added the Package Information table 1, 2, 30 2 DESCRIPTION