CS4172 CS4172 Single Air-Core Gauge Driver Features Description The CS4172 is a monolithic BiCMOS integrated circuit used to translate a digital 10-bit word from a microprocessor/microcontroller to complementary DC outputs. The DC outputs drive an air-core meter commonly used in vehicle instrument panels. The 10 bits of data are used to linearly control the quadrature coils of the meter directly with a 0.35° resolution and ±1.0° accuracy over the full 360° range of the gauge. The interface from the microcontroller is by a Serial Peripheral Interface (SPI) compatible serial connection using up to a 2MHz shift clock rate. The digital code, which is directly proportional to the desired gauge pointer deflection, is shifted into a DAC and multiplexer. These two blocks provide a tangential conversion function to change the digital data into the appropriate DC coil voltage for the angle demanded. The tangential algorithm creates approximately 40% more torque in the meter movement than does a sin-cos algorithm at 45°, 135°, 225°, and 315° angles. This increased torque reduces the error due to pointer droop at these critical angles. Each output buffer is capable of supplying up to 80mA per coil and are controlled by a common enable pin. When OE is low the output buffers are turned off but the logic portion of the chip remains powered and continues to operate normally. The Serial Gauge Driver is self-protected against output short circuit conditions. The output drivers are disabled anytime the on-chip protection circuitry detects a short circuit condition. The outputs remain off until a falling edge is presented on CS. If the short circuit is still present the output drivers automatically disable themselves again. A thermal protection circuit limits the junction temperature to approximately 160°C for conditions of high supply voltage and high ambient temperature. The status pin (ST) reflects the state of the outputs and is low whenever the outputs are disabled. Block Diagram VBB VCC ■ Serial Input Bus ■ 2MHz Operating Frequency ■ Tangential Drive Algorithm ■ 80mA Drive Circuits ■ 0.5° Accuracy (Typ.) ■ Power-On-Reset ■ Protection Features Output Short Circuit Overtemperature Package Options 16 Lead PDIP SIN- 1 SIN+ COS- Gnd Gnd VBB Gnd SO NC SI ST VCC CS OE POR SI SCLK CS SCLK LOGIC SIN+ Serial to Parallel Shift Register COS+ VTOP D0 – D6 7 Bit DAC VVAR SIN– MUX COS+ VBAT SO COS– D7 – D9 OC R FAULT S Latch S Output Amplifiers POR ST 16 Lead SO Wide Internally Fused Leads SINSIN+ 1 COS+ COS- VBB SO Gnd Gnd Gnd Gnd SI ST VCC CS OE SCLK OE Gnd ON Semiconductor 2000 South County Trail, East Greenwich, RI 02818 Tel: (401)885–3600 Fax: (401)885–5786 N. American Technical Support: 800-282-9855 Web Site: www.cherry–semi.com August, 1999 - Rev. 2 1 CS4172 Absolute Maximum Ratings Supply Voltage VBB .................................................................................................................................................................. −1.0V to 15.0V VCC .................................................................................................................................................................... −1.0V to 6.0V Digital Inputs ............................................................................................................................................................ −1.0V to 6.0V Ground Potential Difference (|AGnd-DGnd|)................................................................................................................... 0.5V Steady State Output Current ........................................................................................................................................... ±100mA Forced Injection Current (Inputs and Supply)................................................................................................................ ±10mA Operating Junction Temperature (TJ) ................................................................................................................................. 150°C Storage Temperature Range ................................................................................................................................ −65°C to 150°C Lead Temperature Soldering Wave Solder (through hole styles only) .................................................................................... 10 sec. max, 260°C peak Reflow (SMD styles only) ..................................................................................... 60 sec. max above 183°C, 230°C peak ESD Susceptibility (Human Body Model)............................................................................................................................. 2kV Electrical Characteristics: −40°C ≤ TA ≤ 105°C; 7.5V ≤ VBB ≤ 14V; 4.5V ≤ VCC ≤ 5.5V; unless otherwise specified. PARAMETER TEST CONDITIONS MIN ■ Supply Voltages and Currents Output disabled (OE = 0V) VBB Quiescent Current [RCOS, RSIN = RL(MIN)] @ 45° (code = X’080) VBB = 14V VCC Quiescent Current OE = high, VBB = 0V SCLK = 2.0MHz ■ Digital Inputs and Outputs Output High Voltage Output Low Voltage Output High Current Input High Voltage Input Low Voltage Input High Current Input Low Current ■ Analog Outputs Output Function Accuracy Output Shutdown Current, Source Output Shutdown Current, Sink Output Shutdown Current, Source Output Shutdown Current, Sink Coil Drive Output Voltage Minimum Load Resistance SO, IOH = 0.8mA SO, IOL =0.8mA ST, IOL = 2.5mA ST, VCC = 5.0V CS, SCLK, SI, OE CS, SCLK, SI, OE CS, SCLK, SI, OE; VIN = 0.7 × VCC CS, SCLK, SI, OE; VIN = 0.3 × VCC TYP 1 MAX UNIT 5 175 mA mA 1 mA VCC − 0.8 0.4 0.8 25 0.7 × VCC 0.3 × VCC 1 1 V V V µA V V µA µA −1.2 +1.2 deg VBB = 14.0V 70 250 mA VBB = 14.0V 70 250 mA VBB = 7.5V 43 250 mA VBB = 7.5V 43 250 mA 0.748 × VBB 229 171 150 TA = 105°C TA = 25°C TA = −40°C 2 V Ω Ω Ω PARAMETER TEST CONDITIONS Shift Clock Frequency SCLK High Time SCLK Low Time SO Rise Time SO Fall Time SO Delay Time SI Setup Time SI Hold Time CS Setup Time CS Hold Time MIN TYP MAX 2.0 175 175 0.75V to VCC − 1.2V; CL = 90pF 0.75V to VCC − 1.2V; CL = 90pF CL = 90pF 150 150 150 75 75 0 75 UNIT MHz ns ns ns ns ns ns ns ns ns Package Pin Description PACKAGE PIN# PIN SYMBOL FUNCTION 16 Lead SO Wide 1 2 3 4,5,12,13 6 16 Lead PDIP 1 2 4 3,13,14 6 SIN− SIN+ VBB Gnd SI Negative output for SINE coil. Positive output for SINE coil. Analog supply. Nominally 13.5V. Ground. Serial data input. Data present at the rising edge of the clock signal is shifted into the internal shift register. 7 7 VCC 8 8 OE 9 9 SCLK 10 10 CS 11 11 ST 14 5 SO 5V logic supply. The internal registers and latches are reset by a POR generated by the rising edge of the voltage on this pin. Controls the state of the output buffers. A logic low on this pin turns them off. Serial clock for shifting in/out of data. Rising edge shifts data on SI into the shift register and the falling edge changes the data on SO. When high allows data at SI to be shifted into part with the rising edges of SCLK. The falling edge transfers the shift register contents into the DAC and multiplexer to update the output buffers. The falling edge also re-enables the output drivers if they have been disabled by a fault. STATUS reflects the state of the outputs and is low anytime the outputs are disabled, either by OE or the internal protection circuitry. Requires external pull-up resistor. Serial data output. Existing 10-bit data is shifted out when new data is shifted in. Allows cascading of multiple devices on common serial port. 15 15 COS− 16 12 COS+ 16 Negative output for COSINE coil. Positive output for COSINE coil. No connection. NC 3 CS4172 Electrical Characteristics: −40°C ≤ TA ≤ 105°C; 7.5V ≤ VBB ≤ 14V; 4.5V ≤ VCC ≤ 5.5V; unless otherwise specified. CS4172 Applications Information Quadrant II Theory of Operation θ = 180° – Tan−1 The SACD is for interfacing between a microcontroller or microprocessor and air-core meter movements commonly used in automotive vehicles for speedometers and tachometers. These movements are built using 2 coils placed at a 90° orientation to each other. A magnetized disc floats in the middle of the coils and responds to the magnetic field generated by each coil. The disc has a shaft attached to it that protrudes out of the assembly. A pointer indicator is attached to this shaft and in conjunction with a separate printed scale displays the vehicle’s speed or the engine’s speed. 90° 135° 180° 225° 270° 315° ] For θ = 135.176° to 179.824°: VSIN = Tan(180° – θ) × 0.748 × VBB VCOS = −0.748 × VBB Quadrant III θ = 180° + Tan−1 [ VSIN+ – VSIN− VCOS+ – VCOS− ] For θ = 180.176° to 224.824°: VSIN = −Tan(θ – 180°) × 0.748 × VBB VCOS = −0.748 × VBB For θ = 225.176° – 269.824°: VSIN = −0.748 × VBB VCOS = −Tan(270° – θ) × 0.748 × VBB Degrees of Rotation 45° VSIN+ – VSIN− VCOS+ – VCOS− For θ = 90.176° to 134.824°: VSIN = 0.748 × VBB VCOS = −Tan(θ – 90°) × 0.748 × VBB The disc (and pointer) respond to the vector sum of the voltages applied to the coils. Ideally, this relationship folsine lows a cosine equation. Since this is a transcendental and non-linear function, devices of this type use an approximation for this relationship. The SACD uses a tangential algorithm as shown in Figure 1. Only 1 output varies in any 45 degree range. 0° [ 360° Max (128) SIN+ Output Min (0) Quadrant IV Max (128) SIN– Output θ = 360° – Tan−1 Min (0) Max (128) [ VSIN+ – VSIN− VCOS+ – VCOS− ] For θ = 270.176° to 314.824°: VSIN = −0.748 × VBB VCOS = Tan(θ – 270°) × 0.748 × VBB COS+ Output Min (0) Max (128) COS– Output For θ = 315.176° – 359.824°: VSIN = −Tan(360° – θ) × 0.748 × VBB VCOS = 0.748 × VBB Min (0) 000 001 010 011 100 101 110 111 000 MUX bits (D9 – D7) Figure 1. Major gauge outputs. VCOS+ 360/0° Quadrant I θ = Tan−1 [ 0.748VBB VSIN+ – VSIN− VCOS+ – VCOS− ] θ IV For θ = 0.176° to 44.824°: VSIN = Tanθ × 0.748 × VBB VCOS = 0.748 × VBB I 270° VSIN– 0.748VBB 0.748VBB II III For θ = 45.176° to 89.824°: VSIN = 0.748 × VBB VCOS = Tan(90° – θ) × 0.748 × VBB 0.748VBB 180° VCOS− Graph 1. Major gauge response. 4 90° VSIN+ To drive the gauge’s pointer to a particular angle, the microcontroller sends a 10-bit digital word into the serial port. These 10 bits are divided as shown in Figure 2. However, from a software programmers viewpoint, a 360° circle is divided into 1024 equal parts of .35° each. Table 1 shows the data associated with the 45° divisions of the 360° driver. register changes at SO on the falling edge of SCLK. This arrangement allows the cascading of devices. SO is always enabled. Data shifts through without affecting the outputs until CS is brought low. At this time the internal DAC is updated and the outputs change accordingly. CS CSHold CSSetup MSB LSB SCLK Major Gauge (360°) D9 D8 D7 D6 D5 D4 D3 D2 D1 D0 SI(Setup) D9 – D7 select which octant Divides a 45° octant into 128 equal parts to achieve a .35° resolution Code 0 – 12710 SI(Hold) SI Figure 2. Definition of serial word. SO(Rise, Fall) 10% - 90% SO VSIN (V) 0.032 10.476 10.476 10.412 −0.032 −10.476 −10.476 −10.476 −0.032 VCOS (V) 10.476 10.412 −0.032 −10.476 −10.476 −10.412 0.032 10.412 10.476 SO(tpd) Figure 3. Serial data timing diagram. VCC CS SI Table 1. Nominal output for major gauge (VBB = 14V). OE The 10 bits are shifted into the device’s shift register MSB first using an SPI compatible scheme. This method is shown in Figure 3. The CS must be high and remain high for SCLK to be enabled. Data on SI is shifted in on the rising edge of the synchronous clock signal. Data in the shift ST 10 Bits 10 Bits REGISTERS SET TO ZERO Nominal Degrees 0.176 45.176 90.176 135.176 180.176 225.176 270.176 315.176 359.826 REGISTERS SET TO ZERO Input Code Ideal (Decimal) Degrees 0 0 128 45 256 90 384 135 512 180 640 225 768 270 896 315 1023 359.65 OUTPUTS ENABLED Figure 4. Power-up sequence. Application Diagram VBAT VREG CS8156 5V 12V ENABLE 360° Gauge 10k Microcontroller SIN− SIN+ ST CS SI SCLK COS+ COS− VBB VCC CS4172 SO Next Driver OE 5 OUTPUTS ENABLED CS4172 Applications Information: continued CS4172 Package Specification PACKAGE THERMAL DATA PACKAGE DIMENSIONS IN mm (INCHES) D Lead Count Metric Max Min 19.69 18.67 10.50 10.10 16 Lead PDIP 16 Lead SO Wide* English Max Min .775 .735 .413 .398 Thermal Data RΘJC typ 16 Lead PDIP 42 16 Lead SO Wide* 18 °C/W RΘJA typ 80 75 °C/W Plastic DIP (N); 300 mil wide 7.11 (.280) 6.10 (.240) 8.26 (.325) 7.62 (.300) 1.77 (.070) 1.14 (.045) 2.54 (.100) BSC 3.68 (.145) 2.92 (.115) .356 (.014) .203 (.008) 0.39 (.015) MIN. .558 (.022) .356 (.014) REF: JEDEC MS-001 Some 8 and 16 lead packages may have 1/2 lead at the end of the package. All specs are the same. D Surface Mount Wide Body (DW); 300 mil wide 7.60 (.299) 7.40 (.291) 10.65 (.419) 10.00 (.394) 0.51 (.020) 0.33 (.013) 1.27 (.050) BSC 2.49 (.098) 2.24 (.088) 1.27 (.050) 0.40 (.016) 2.65 (.104) 2.35 (.093) 0.32 (.013) 0.23 (.009) D REF: JEDEC MS-013 0.30 (.012) 0.10 (.004) Ordering Information Part Number CS4172XN16 CS4172XDWF16 CS4172XDWFR16 ON Semiconductor and the ON Logo are trademarks of Semiconductor Components Industries, LLC (SCILLC). ON Semiconductor reserves the right to make changes without further notice to any products herein. For additional information and the latest available information, please contact your local ON Semiconductor representative. Description 16 Lead PDIP 16 Lead SO Wide* 16 Lead SO Wide* (tape & reel) *Internally Fused Leads 6 © Semiconductor Components Industries, LLC, 2000 Notes Notes