DS3881 MAXIM [Maxim Integrated Products], DS3881 Datasheet
DS3881
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DS3881 Summary of contents
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... CCFLs used to backlight liquid crystal displays (LCDs) in navigation and infotainment applications and for dri- ving CCFLs used to backlight instrument clusters. The DS3881 is also appropriate for use in marine and avia- tion applications. The DS3881 features EMI suppression functionality and provides a lamp current overdrive mode for rapid lamp heating in cold weather conditions ...
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Single-Channel Automotive CCFL Controller ABSOLUTE MAXIMUM RATINGS Voltage Range SDA, and CC SCL Relative to Ground.....................................-0.5V to +6.0V Voltage Range on Leads Other than V CC SCL ......................-0. 0.5V), not to exceed +6.0V CC ...
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Single-Channel Automotive CCFL Controller ELECTRICAL CHARACTERISTICS (continued +4.75V to +5.25V -40°C to +105°C PARAMETER SYMBOL High-Level Output Voltage (GA, GB) UVLO Threshold: V Rising V CC UVLO Threshold: V Falling V CC UVLO Hysteresis ...
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... Note 4: Lamp overdrive and analog dimming (based on reduction of lamp current) are disabled. Note 5: This is the minimum pulse width guaranteed to generate an output burst, which will generate the DS3881’s minimum burst duty cycle. This duty cycle may be greater than the duty cycle of the PSYNC input. Once the duty cycle of the PSYNC input is greater than the DS3881’ ...
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Single-Channel Automotive CCFL Controller (V = 5.0V +25°C, unless otherwise noted ACTIVE SUPPLY CURRENT vs. SUPPLY VOLTAGE 7.0 DPWM = 100% DPWM = 10% 6.5 DPWM = 50% 6.0 5.5 5.0 SVML< ...
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Single-Channel Automotive CCFL Controller (V = 5.0V +25°C, unless otherwise noted SOFT-START 16V INV 50µs 5. 50µs 5. 50µs 2.00V LCM 50µs 2.00V OVD 6 _____________________________________________________________________ Typical Operating Characteristics ...
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... SCL Serial Clock Input. I Lamp Frequency Input/Output. This pin is the input for an externally sourced lamp frequency when the DS3881 is configured as a lamp frequency receiver. If the DS3881 is configured as a lamp 4 LSYNC frequency source (i.e., the lamp frequency is generated internally), the frequency is output on this pin for use by other lamp frequency receiver DS3881s ...
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... POR POR 8 BYTE USER MEMORY STATUS REGISTERS CHANNEL FAULT FAULT CHANNEL ENABLE HANDLING [40kHz ~ 100kHz] x512 [20.48MHz ~ 51.20MHz] PLL LFSS BIT AT CR1.2 DS3881 DPSS BIT AT CR1.3 MUX RGSO BIT AT CR1.4 MUX RAMP POSCS BIT GENERATOR AT CR1.1 Functional Diagrams V CC [4.75V TO 5.25V] ...
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... RMS Block diagrams of the DS3881 are shown in Figures 1 and 2. More operating details of the DS3881 are dis- cussed on the following pages of this data sheet C-Compatible Serial Interface The DS3881 uses an I communication with the on-board EEPROM and SRAM configuration/status registers as well as user memory ...
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... The internally generated DPWM signal can be provided at the PSYNC I/O pin (set RGSO = 0 in CR1) for sourc- ing to other DS3881s, if any, in the circuit. This allows all DS3881s in the system to be synchronized to the same DPWM signal. A DS3881 that is generating the DPWM signal for other DS3881s in the system is referred to as the DPWM source ...
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... Lamp Frequency Configuration The DS3881 can generate its own lamp frequency clock internally (set LFSS = 0 in CR1), which can then be sourced to other DS3881s if required, or the lamp clock can be supplied from an external source (set LFSS = 1 in CR1). When the lamp clock is internally generated, the frequency (40kHz to 100kHz) is set by an external resistor at the LOSC ...
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... TO 440Hz) LSYNC N.C. POSC RESISTOR-SET LOSC LAMP FREQUENCY BRIGHT PSYNC LSYNC N.C. POSC N.C. LOSC Figure 5. Frequency Configuration Options for Designs Using Multiple DS3881s 12 ____________________________________________________________________ ANALOG BRIGHTNESS 0.5V DS3881 LAMP CLOCK (40kHz TO 100kHz) LAMP FREQUENCY SOURCE DPWM SOURCE RESISTOR-SET DIMMING FREQUENCY DS3881 LAMP FREQUENCY RECEIVER ...
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... Single-Channel Automotive CCFL Controller At the beginning of each lamp burst, the DS3881 pro- vides a soft-start that slowly increases the MOSFET 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 ...
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... Control Register 2 (CR2) Table 6 in the Detailed Register Descriptions section. Example: Selecting the resistor values to configure a DS3881 to have a 50kHz lamp frequency and a 160Hz dimming clock frequency: For this configuration, POSCR0 and POSCR1 must be programmed to 1 and 0, respectively, to select 90Hz to 220Hz as the dimming clock frequency range. This sets K for the dimming ) calculation to 4kΩ ...
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... Single-Channel Automotive CCFL Controller Figure 8 shows a flowchart of how the DS3881 controls and monitors each lamp. The steps are as follows: 1) Supply Check—The lamps do not turn on unless the DS3881 supply voltage is above 4.3V and the volt- age at the supply voltage monitors, SVML and SVMH, are respectively above 2.0V and below 2.0V. 2) Strike Lamp— ...
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Single-Channel Automotive CCFL Controller DEVICE AND INVERTER SUPPLIES AT PROPER LEVELS? RESET FAULT COUNTER AND FAULT OUTPUT FAULT_RT STATUS BIT STRIKE LAMP [RAMP AND REGULATE TO OVD THRESHOLD] IF LAMP REGULATION THRESHOLD IS MET RUN LAMP LAMP OVERCURRENT [REGULATE LAMP ...
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... Note 1: E0h–E3h are SRAM locations, and F0h–FFh are SRAM-shadowed EEPROM. Note 2: Altering the DS3881 configuration during active CCFL operation can cause serious adverse effects. Another feature the DS3881 offers is the ability to over- drive the lamps to allow them to heat up quickly in cold environments ...
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Single-Channel Automotive CCFL Controller Table 2. Status Register 1 (SR1) [SRAM, E0h] POWER-UP BIT R/W NAME DEFAULT FAULT_RT FAULT_L STO_L OV_L LOUT_L ...
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Single-Channel Automotive CCFL Controller Table 4a. Soft-Start Protocol Registers (SSPx) [Shadowed-EEPROM, F0h, F1h, F2h, F3h] FACTORY SSP# ADDR DEFAULT SSP1 F0h 21h SSP2 F1h 43h SSP3 F2h 65h SSP4 F3h 77h Table 4b. MOSFET Duty Cycle (MDC)Codes for Soft-Start Settings ...
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Single-Channel Automotive CCFL Controller Table 5. Control Register 1 (CR1) [Shadowed-EEPROM, F4h] FACTORY BIT R/W NAME DEFAULT 0 R/W 0 LOCE 1 R/W 0 POSCS 2 R/W 0 LFSS 3 R/W 0 DPSS 4 R/W 0 RGSO 5 R/W 0 ...
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Single-Channel Automotive CCFL Controller Table 6. Control Register 2 (CR2) [Shadowed-EEPROM, F5h] BIT R/W DEFAULT NAME 0 R/W 0 UMWP 1 R/W 0 POSCR0 2 R/W 0 POSCR1 3 R/W 1 LSR0 4 R/W 0 LSR1 5 — 0 RSVD ...
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Single-Channel Automotive CCFL Controller Table 7. EMI Control Register (EMIC) [Shadowed-EEPROM, F6h] FACTORY BIT R/W NAME DEFAULT 0 R/W 0 SS0 1 R/W 0 SS1 2 R/W 0 SSM 3 RSVD 4 R/W 0 STEPE 5 R/W 0 ...
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Single-Channel Automotive CCFL Controller Table 8. Lamp Current Overdrive Control Register (LCOC) [Shadowed-EEPROM, F7h] FACTORY BIT R/W NAME DEFAULT 0 R/W 0 LCO0 1 R/W 0 LCO1 2 R/W 0 LCO2 3 R/W 0 LCOE 4 R/W 0 TO0 5 ...
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Single-Channel Automotive CCFL Controller The following terminology is commonly used to 2 describe I C 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. ...
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... It is possible to take advantage of that phenomenon by repeatedly addressing the DS3881, which allows the next byte of data to be written as soon as the DS3881 is ready to receive the data. The alternative to acknowl- edge polling is to wait for a maximum period of t elapse before attempting to write again to the DS3881 ...
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... MOSFETs. The transformer should be able to operate in the 40kHz to 80kHz frequency range of the DS3881, and the turns ratio should be selected so the MOSFET drivers run at 28% to 35% duty cycle during steady state operation. The transformer must be able to withstand the high open-circuit voltage that is used to strike the lamp ...
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... MAX 200 500 12 185 70 500 NOTES to r each i ts nor ati ng l evel . each i ts nor ati ng l evel . and GND on DS3881. CC UNITS kHz W mA mΩ Ω µH mH µ RMS 27 ...
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... Dallas Semiconductor Corporation. Heaney DEVICE SUPPLY VOLTAGE (5V ±5 SVMH SVML R5 GA1 DS3881 GB1 DUAL POWER MOSFET OVD1 LCM1 C8 GND For the latest package outline information www.maxim-ic.com/DallasPackInfo. Printed USA is a registered trademark of Maxim Integrated Products, Inc. Typical Operating Circuit ...