Digitally Controlled Potentiometers

Transcription

1 Digitally Controlled Potentiometers Jim McCreary Ph.D., VP Technology 2004/12/23 icor Proprietary Information 1 JM

2 Outline: Digitally Controlled Potentiometers DCP Fundamentals Existing DCP Family 1024 Tap Family 256 Tap Family Dual Interface 9252 Dual Wiper, Dual Interface 9455 High Terminal Voltage 9318/19 Low-Cost, High-Volume 32 Tap DCP DCP Applications Customer Support Tools 2004/12/23 icor Proprietary Information Page 2 JM

3 DCP Fundamentals -- Block Diagram icor Invented DCP Over 15 Years Ago VCC Supply Voltage RH RH Serial Interface Control And Memory RW RW RL EEPROM Non-volatile Memory Switches connected To Taps on Resistor string icor Has the Largest Most Diverse Family of Digitally Controlled Potentiometers 2004/12/23 icor Proprietary Information Page 3 JM MOS switches make-before-break (no glitch) RL

4 DCP Fundamentals -- Typical DCP Architecture Digital Control of Analog Circuits Serial Interface Interface and Control POR Data Register D0 Data Register D1 Data Register D2 Data Register D3 Wiper Counter Register RH RW RL 2-Wire (I2C compatible) 3-Wire (Up/Down) SPI POR Circuit Loads Contents of D0 into WCR at Power-up EEPROM Memory Allows 4 Non-volatile Programmable Registers WCR is Volatile Register Containing the Current Tap Setting Non-Volatile EEPROM Memory is the Key To Calibration Applications 2004/12/23 icor Proprietary Information Page 4 JM

5 DCP Fundamentals -- Voltage Divider or Resistor Applications Assume N Tap DCP with RTOT and tap setting at nth Tap Used as a voltage divider VCC Used as a variable resistor VCC VOUT = n N VCC IOUT = N n VCC RTOT A DCP can Replace a DAC. But a DAC cannot Replace a DCP 2004/12/23 icor Proprietary Information Page 5 JM

6 DCP Fundamentals -- Typical Specifications Wide Range of RTOT Available from 1KΩ to 100KΩ ANALOG CHARACTERISTICS Limits Symbol Parameter Min Typ Max Units RTOTAL End to End Resistance 100 kω End to End Resistance Tolerance 20 % I W Wiper Current 3 ma R W Wiper Resistance Ω VTERM RH,RL,RWTerminal Voltages V Absolute Linearity 1 MI Relative Linearity 0.2 MI Temperature Coefficient of RTOTAL 300 ppm/ C Ratiometric Temp. Coefficient 20 ppm/ C icor Has Larger Wiper Currents icor Has Terminal Voltages icor Has Low Temperature Coefficient 2004/12/23 icor Proprietary Information Page 6 JM

7 DCP Fundamentals Application For Board Calibration During Manufacturing Typical Application: Replacement of mechanical potentiometers used for gain and offset calibration Transimpedance Amplifier - Calibration Step 1 Calibrate adjust I S R F VO = I S R F Step 2 Measure + Save setting Advantages of DCPs over Mechanical Potentiometer Step 3 Store Resistor value into Nonvolatile Memory 1. Can be calibrated automatically during electrical test, 2. No need for mechanical adjustment 3. Not sensitive to mechanical vibration 4. Smaller board space (Quad DCP in one package) Step 4 Automatic Recall from Memory Power Up 2004/12/23 icor Proprietary Information Page 7 JM

8 DCP Fundamentals The wiper tap setting stored in NV memory is recalled during Power-up V CC POR Circuit Non-volatile Memory EEPROM Wiper Counter Register Resistor Tap Setting Is Restored 1. When Vcc reaches Vtrip 2. The EEPROM is read and The internal circuit then loaded into the WCR automatically Generates a recall pulse 3. The Tap setting changes to setting last saved in EEPROM Initial power-up value Restored Tap setting 2004/12/23 icor Proprietary Information Page 8 JM

9 DCP Family Tree 2004/12/23 icor Proprietary Information Page 9 JM

10 1024 Tap DCP Family 2004/12/23 icor Proprietary Information 10 JM

11 9119/ Tap, 100KΩ, 2-wire bus, Single Supply (9111 SPI bus) V CC R H I 2 C2-wire bus bus interface address data status BUS INTERFACE CONTROL & REGISTER write read store control Power On Recall Wiper Counter Register (WCR) Data Registers (DR0-DR3) wiper 100Kohm 1024-taps POT V SS NC NC R W R L icor was the first to offer 1024 tap DCP 2004/12/23 icor Proprietary Information Page 11 JM

12 9118/ Tap, 100KΩ, 2-wire bus, Dual Supply (9110 SPI bus) V CC R H V+ 2-wire I 2 C bu s bus interface interface ad dress data status BUS INTERFACE CON TROL & RE GISTER write re ad store control Power On Recall Wiper Counter Register (WCR) Data Registers (DR0-DR3) wiper 100Kohm 1024-taps POT V SS NC NC R W R L V- 2004/12/23 icor Proprietary Information Page 12 JM

13 1024 Tap DCPs Features and Benefits icor offers 2 different interfaces 2wire & SPI to meet the system needs of a wide-range of applications DCP Options: Single Supply DCP Terminal Voltage: 0 5.5V Dual Supply DCP Terminal Voltage: from -5.5V to +5.5V 100KΩ end-to-end variable resistance 3uA Standby current allows battery applications Less than 0.5bit (0.5MI) error in relative linearity Less than 300 ppm/ C Available in CSP (flip chip) 2004/12/23 icor Proprietary Information Page 13 JM

14 256 Tap DCP Family 2004/12/23 icor Proprietary Information 14 JM

15 256 Tap DCP Family DCP Number Taps Interface Rtot KΩ Single Supply Dual Supply 2.7v-5.5v 4.5v-5.5v Vterm Iwiper ma Rwiper Ω Isb A 9271 Single 256 SPI to Single wire to Dual 256 SPI to Dual 256 SPI to Dual wire to Dual wire to Dual wire, 3 wire 2, 10, 50, to Quad 256 SPI 50, to Quad 256 SPI 50, to Quad wire, 3 wire 2, 10, 50, to Quad wire 50, to Quad wire 50, to More product options than competition 2004/12/23 icor Proprietary Information Page 15 JM

16 9259 Block Diagram Typical 1000Ω Wiper Resistance and 0.2 LSB Differential Linearity and 5 A Max Standby Current 2004/12/23 icor Proprietary Information Page 16 JM

17 9252 Quad 256Tap DCP with Dual Interface First Dual Interface DCP that allows both initial calibration and also realtime dynamic control Aimed at high-performance systems which require minor (single step) adjustments in tap position during operation Allows dynamic optimization of system performance 2004/12/23 icor Proprietary Information Page 17 JM 2.8K,10K,50K,100K ohm Options Typical 50Ω Wiper Resistance and 0.2 LSB Differential Linearity

18 Initial Calibration and Dynamic Control Initial calibration at board mfg through 2-wire interface as usual Dynamic control of one DCP during real-time operation Temp Compensated Reference Voltage SCL DS0 DS Pot 0 V Temp V U/D CS Logic And Control Analog System Error signal By controlling DS0 and DS1, other POTS can also be dynamically controlled At the same time Control possible without up 2004/12/23 icor Proprietary Information Page 18 JM

19 9455 Dual 2-wiper 256Tap DCP with Dual Interface 2-wipers on the same resistor allow very accurate differential voltage adjustment over wide common-mode voltage range Aimed at window voltage applications required by sensors used for voltage, current, temperature, pressure monitors 2.8K,10K,50K,100K ohm Options Typical 50Ω Wiper Resistance and 0.2 LSB Differential Linearity 2004/12/23 icor Proprietary Information Page 19 JM

20 Application of 9455 to Sensor Alarm Circuit 9455 Sets Allowable Range for Safe Operation Window Comparator Upper Limit Lower Limit VREF Over / Under Voltage Alarm Vx Sensor Voltage 2004/12/23 icor Proprietary Information Page 20 JM

21 9252 and 9455 Features and Benefits Quad or Dual 256Tap DCP Non-volatile storage of wiper positions Initial Calibration and control setting through fast 2-wire interface Dynamic control through U/D interface Each DCP can be addressed through either interface at any time Wiper resistance 40Ω Wiper currents up to 3mA Vcc from 2.7 to 5.5V Rtot Options: 2.8K, 10K, 50K, 100K 2004/12/23 icor Proprietary Information Page 21 JM

22 9252 and 9255 Temperature and Noise Dependence 100K and 50K Rtot Temperature Coefficient - 400ppm/C from - 40C to 25C 100ppm/C from 25C to 85C. 10K Rtot Temperature Coefficient -180ppm/C from - 40C to 25C 120ppm/C from 25C to 85C. 2.8K Rtot Temperature Coefficient ppm/C. 3.5uV RMS noise on Vw at Middle Tap 10Hz to 22KHz bandwidth 2004/12/23 icor Proprietary Information Page 22 JM

23 9318 8V and V DCPs Jim McCreary 2004/12/23 icor Proprietary Information 23 JM

24 9318 and 9319 Higher DCP Terminal Voltage V FEATURES Solid-state potentiometer 3-wire serial interface Terminal voltage, 0 to +8V 100 wiper tap points Wiper position stored in NV memory and recalled on power-up 99 resistive elements Temperature compensated End to end resistance range 20% Low power CMOS VCC = 5V Active current, 3mA max. Standby current, 1mA max. High reliability Endurance, 100,000 data changes per bit Register data retention, 100 years RTOTAL value = 10K Packages 8-lead SOIC and DIP V FEATURES Solid-state potentiometer 3-wire serial interface Terminal voltage, 0 to +10V 100 wiper tap points Wiper position stored in NV memory and recalled on power-up 99 resistive elements Temperature compensated End to end resistance range 20% Low power CMOS VCC= 5V Active current, 3mA max. Standby current, 1mA max. High reliability Endurance, 100,000 data changes per bit Register data retention, 100 years RTOTAL value = 10KΩ and 50KΩ Packages 8-lead SOIC and DIP Differences DCP Terminal Voltage RTOTAL Options 2004/12/23 icor Proprietary Information Page 24 JM

25 APPLICATIONS LCD bias control DC bias adjustment Gain and offset trim Laser diode bias control Voltage regulator output control Market Applications: Automotive, Audio, Power Supplies, Industrial Control 2004/12/23 icor Proprietary Information Page 25 JM

26 93154 DCP Family Jim McCreary 2004/12/23 icor Proprietary Information 26 JM

27 Tap DCP Special Features Applications: High-Volume, Low-Cost, low power Non-volatile memory required for set & forget Low 400uA programming current allows in-circuit programming Low Isb <1uA, low battery drain Operation at 2.7V allows supply compatibility U/D interface allows easy adjustment Low 100ppm/ C Rot temperature coefficient INC U/D RH POR Control RDCP Vcc 30K CS RL Robust POR Control compatible with battery powered application lacking up Vss NC 0.6u Process allows low cost Available in chip-scale package 1mm x 1mm Target Markets: LCD Contrast for Cell phone, handheld, battery charger, consumer, small appliance, Price: $0.38 / 1KU! In FCP (chipscale) pkg 2004/12/23 icor Proprietary Information Page 27 JM

28 Application Schematic of in LCD Contrast Control Vout can be +15V 3V 10% + R INC Vcc Vref R2 U/D POR Control 30K CS R1 Vout = Vref ( 1 + ) R2 + RDCP Temperature Compensation for LCD Added to Vref(T) RH Vss RDCP RL NC As long as RDCP TCR is small, then Vout(T) set by Vref(T) R1 and R2 allow high resolution between Vout(max) and Vout(min) 2004/12/23 icor Proprietary Information Page 28 JM

29 Cell Phone Application Special Requirements Fast Vcc ramp rate tolerance To pass Drop Test Interface pins and Vcc sequence independence To allow external tester to program the module Initially disabled CS to prevent accidental write during power-up On-chip 30KΩ pull-up resistor on CS pin To disable CS when CS pin is open-circuit Small size chip scale package Reduces cost and board space Low standby and programming current Non-volatile E2 memory for wiper position provides all of the above 2004/12/23 icor Proprietary Information Page 29 JM

30 Fast Vcc ramp rate tolerance Drop test is momentary battery disconnect Generates Vcc ramp rate equivalent to 10KV/ms provides on-chip 880 S delay before recall This has effect of slowing down Vcc ramp rate to equivalent ramp rate of 2V/ms Vcc Effective rate 2V/mS 880 s Recall Stored Data 2004/12/23 icor Proprietary Information Page 30 JM

31 Interface pins and Vcc sequence independence New ESD on CS, INC and U/D pins eliminates diode to Vcc This allows CS, INC and U/D pins to go above Vcc during power up At steady state interace pins must be either Vss or Vcc Vcc CS INC U/D RH RL Vss 2004/12/23 icor Proprietary Information Page 31 JM

32 Initially disabled CS CS internally disabled for 880 s Then CS is only enabled after CS pin is high Vcc CS initially disabled CS enabled CS enabled 880 s 2004/12/23 icor Proprietary Information Page 32 JM

33 On-chip 30KΩ pull-up resistor on CS pin Allows CS pin to float after LCD module calibration is completed 30KΩ pull-up Vcc CS INC U/D RH RL Vss 2004/12/23 icor Proprietary Information Page 33 JM

34 FCP Flip Chip Package 2004/12/23 icor Proprietary Information Page 34 JM

35 2004/12/23 icor Proprietary Information Page 35 JM

36 93154 DCP Family DCP # DCP Terminals Vcc V 10% V 10% V~5.5V V 10% 2004/12/23 icor Proprietary Information Page 36 JM

37 DCP APPLICATIONS 2004/12/23 icor Proprietary Information Page 37 JM

38 DCP Applications Data Communications RF gain control Laser Diode Control Consumer Consumer Audio. Volume/Tone control or adjustment Video. Filter Gain and frequency control or adjustment PC / Computer Displays. LCD Backlight. Contrast and Brightness(Dimming) control or adjustment LCD Displays. PC market, Cell-phone PDA or handhelds. Active Matrix / Passive Matrix / EL (electroluminescent) DC Power Supplies. DC-to-DC voltage regulation 2004/12/23 icor Proprietary Information Page 38 JM

39 DCP Applications SOHO and Office Automation Copiers and Printers. Controls Automotive Engine control, speed control, Instrument Panel Safety: braking, tire pressure, proximity detectors Consumer Consumer Audio. Volume/Tone control or adjustment Video. Filter Gain and frequency control or adjustment 2004/12/23 icor Proprietary Information Page 39 JM

40 DCP Applications SOHO and Office Automation Copiers and Printers. Controls Industrial Oscillator and Timers. Frequency and phase control or adjustment Temperature / Pressure Sensors. Industrial displays. Contrast, Brightness, Gamma Correlation. Plasma, Electroluminescent (EL), TFT/Passive Matrix LCD Examples: PWM dimming Lighting controls. High power. Occupancy sensor / Architectural Dimming (i.e. 0-to-10Vdimming, PWM dimming) Remote monitoring/metering (i.e. RF communication) Industrial/Medical Equipment. Calibration and Measurement. Handhelds. Battery Charging control Servo motor control 2004/12/23 icor Proprietary Information Page 40 JM

41 DCP Applications SOHO and Office Automation Copiers and Printers. Controls Industrial Oscillator and Timers. Frequency and phase control or adjustment Temperature / Pressure Sensors. Industrial displays. Contrast, Brightness, Gamma Correlation. Plasma, Electroluminescent (EL), TFT/Passive Matrix LCD Examples: PWM dimming Lighting controls. High power. Occupancy sensor / Architectural Dimming (i.e. 0-to-10Vdimming, PWM dimming) Remote monitoring/metering (i.e. RF communication) Industrial/Medical Equipment. Calibration and Measurement. Handhelds. Battery Charging control Servo motor control 2004/12/23 icor Proprietary Information Page 41 JM

42 CUSTOMER SUPPORT TOOLS LabView Kit Allows Customer to Perform Quick Efficient Evaluation Application Notes to Assist Customer During Design Phase Contact icor at /12/23 icor Proprietary Information Page 42 JM

43 Customer Support Tools -- LabView Kit Evaluation Boards For icor Products including software drivers Hardware allows electrical evaluation by direct measurement Allows insertion of icor Product into customer system for evaluation LabVIEW Software for Graphical User Interface Allows Read/Write Access to Registers, EEProm and Programmable Features 2004/12/23 icor Proprietary Information Page 43 JM

44 END icor The World s Leader In Digitally Controlled Potentiometers! 2004/12/23 icor Proprietary Information Page 44 JM