IC-MLEVALML1D

iC-ML HALL Position Sensor / Encoder Rev A3, Page 1/17 FEATURES o Linear Hall sensor array for magnetic pole pitch of 2.56 mm o Non-sensitive to magnetic stray fields due to differential measurement technique o Interpolator with 8-bit linear resolution of 20 µm o Linear speed up to 5 m/s o Buffered I/O stages for signal outputs o Configuration inputs for operating mode selection o Analog operation modes: - sine/cosine signals controlled to 2 Vpp - triange or sawtooth signal with selectable amplitude o Digital operation modes: - A/B quadrature signals with Z index pulse - Counter pulses for external binary counters o Cascading of multiple iC-ML possible for chain operation (Evaluation of independent scales x, y, z) o Error signal output for detection of low magnetic field strength o Additional operating modes with reduced power consumption o Standby modus when not enabled o Extended temperature range of -40...+125 °C APPLICATIONS o o o o o o o o Analog and digital linear sensors Incremental linear encoders Pole wheel sensing Potentiometer replacement Contactless slider/switch Commutation of linear motor Absolute displacement sensing Liquid level meter PACKAGES VDD CFG3 C CFG1 D NEN A GND CFG2 B TSSOP20 Die-Size 4.4 mm x 1.9 mm BLOCK DIAGRAM VDD VDD CFG1 SIN SIN I/O DIG 8 BIT AMP I/O A VDD COS CFG2 HALL SENSOR GAIN VDD B CFG3 SIN +COS GAIN CONTROL 2 2 iC-ML REFH VPHI C I/O D NEN VDD I/O VREF MODE SELECT BIAS AMPLITUDE ERROR CONTROL GND DIG/R REFL INTERFACE Copyright © 2009 iC-Haus http://www.ichaus.com iC-ML HALL Position Sensor / Encoder Rev A3, Page 2/17 DESCRIPTION The CMOS device iC-ML consists of four hall sensors arranged in a line and optimized to read out magnetic tapes with 2.56 mm pole spacing. This sensor array permits error-tolerant adjustment of the magnetic tape, reducing assembly efforts. The integrated signal conditioning unit provides a differential sine/cosine signal at the output. The sensor generates one sine/cosine cycle for each full magnetic periode of 5.12 mm, enabling the travelling distance to be clearly determined. At the same time the internal amplitude control unit produces an regulated output amplitude of 2 Vpp regardless of variations in the magnetic field strength, supply voltage and temperature. Furthermore, signals are provided which enable the sensor amplitude to be assessed and also report any magnetic tape loss. With the aid of the integrated 8-bit sine/digital converter the travelling distance within a magnetic periode is determined from the sine/cosine signals. This is output via an incremental interface in a number of selectable resolutions. The zero position of each periode is indicated by an index pulse. The maximum resolution of 8-bit is maintained up to travelling speeds of 5 m/s. The absolute position within a magnetic periode can be converted back to a linear analog output signal using the internal D/A converter; here, output voltage limits can be set as required using the external pins. Either a periodic linear signal (sawtooth) or a delta voltage (triangle) can be provided. iC-ML can be easily cascaded in three different modes of chain operation so that several axes of transistion can be scanned. The linear positions of the individual axes can then be read via a common bus. Used in conjunction with a magnetic tape iC-ML can act as an linear encoder system with an integrated magnetic scanning feature. PACKAGES TSSOP20 PIN CONFIGURATION - TSSOP20 PIN FUNCTIONS No. Name Function 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 T0 NEN n.c. GND n.c. CFG2 B n.c. A n.c. VTC D n.c. C CFG3 n.c. VDD n.c. CFG1 VTS Test Pin (connect to GND) Enable Input, low active Ground Configuration Input 2 Bidirectional Input/Output B Bidirectional Input/Output A Test Pin (do not connect) Bidirectional Input/Output D Bidirectional Input/Output C Configuration Input 3 +5 V Supply Voltage Configuration Input 1 Test Pin (do not connect) iC-ML HALL Position Sensor / Encoder Rev A3, Page 3/17 ABSOLUTE MAXIMUM RATINGS Beyond these values damage may occur; device operation is not guaranteed. Item No. Symbol Parameter Supply voltage Voltages at A, B, C, D, NEN, CFG1, CFG2 Current at VDD Current at A, B, C, D, NEN, CFG1, CFG2 Pulse current (Latch-up immunity) ESD-Voltage at all pins Storage temperature Pulse width < 10 µs HBM, 100 pF discharged over 1.5 kΩ -40 V() < VDD + 0.3 V Conditions Min. -0.3 -0.3 -30 -30 -10 -100 Max. 6 6 30 30 10 100 2 150 V V mA mA mA mA kV °C Unit G001 VDD G002 V() G003 Imx(VDD) G005 Imx() G006 Ilu() G007 Vd() G008 Ts G004 Imx(GND) Current at GND THERMAL DATA Operating conditions: VDD = 5 V ±10 % Item No. T01 T02 Symbol Ta Rthja Parameter Ambient temperature Thermal resistance chip/ambient SMD assembly, no additional cooling areas Conditions Min. -40 Typ. Max. 125 75 °C K/W Unit All voltages are referenced to ground unless otherwise stated. All currents into the device pins are positive; all currents out of the device pins are negative. iC-ML HALL Position Sensor / Encoder Rev A3, Page 4/17 ELECTRICAL CHARACTERISTICS Operating conditions: VDD = 5 V ±10 % , Tj = -40 ... 125 °C, unless otherwise noted Item No. 001 002 003 004 005 101 102 103 104 105 106 107 Symbol Parameter Conditions Min. VDD I(VDD) I(VDD)sb Supply voltage Supply current Standby supply current open pins, normal operation open pins, power reduction mode (PRM) NEN = VDD VDD > 4 V, see Fig. 9 VDD < 2.6 V 20 10 10 50 1.28 0.7 -0.2 -0.2 -3 400 0.2 0.2 3 100 4.5 Typ. 5 14 7 Max. 5.5 20 10 200 V mA mA µA µs µs kA/m mm mm mm mm DEG µm Unit General td(VDD)on Turn on delay td(VDD)off Turn off delay Hext psens ysens xdis ydis Φ dis hsens Hall sensor array Requiered external magnetic field at chip surface strength Hall sensor array pitch Hall sensor array distance to center of die Lateral displacement of chip to package Vertical displacement of chip to package see Fig. 1 see Fig. 1 in TSSOP20 package, see Fig. 2 in TSSOP20 package, see Fig. 2 Angular displacement of chip with in TSSOP20 package, see Fig. 2 reference to package Distance chip surface to top of package Offset voltage Temperatur coefficient of offset voltage Output mean value Amplitude ratio of SIN / COS Cut off frequency Settling time Gain output voltage Sine/Cosine amplitude Relative angular error Oscillator frequency Temperature coefficient of oscillator frequency Converter hysteresis Threshold voltage high Threshold voltage low Open circuit voltage Input resistance Threshold voltage high Threshold voltage low Hysteresis Pull-up current Saturation voltage high Saturation voltage low Rise time Vt()hys = Vt()hi - Vt()lo V() = 0...VDD - 1 V Vs()hi = VDD - V(), I() = -4 mA I() = 4 mA CL() = 50 pF V()ampl = V()max - Vdc with reference to one periode, see Fig. 3 to 70 % amplitude, Hext = 40 kA/m in TSSOP20 package, see Fig. 2 Signal conditioning 201 202 203 204 205 206 207 208 301 302 303 304 401 402 403 404 501 502 503 504 601 602 603 Voff TC(Voff) Vdc Ratio fhc t()settle V()gain V()ampl AArel f(OSC) TC(OSC) hys Vt()hi Vt()lo V0() Ri() Vt()hi Vt()lo Vt()hys Ipu() Vs()hi Vs()lo tr() on output, with external magnetic field amplitude of 20 kA/m -50 -50 45 0.95 50 1.00 20 80 0.05 0.9 -20 200 256 -0.1 1 60 25 43 45 150 78 40 57 450 2 0.8 300 -240 -120 -25 0.4 0.4 60 1.0 150 4.0 1.1 20 300 50 50 55 1.05 kHz µs V V % kHz %/K LSB % VDD % VDD % VDD kΩ V V mV µA V V ns mV µV/K %VDD Sine-to-digital converter Configuration inputs CFG1, CFG2, CFG3 Enable input NEN Digital outputs: A, B, C, D iC-ML HALL Position Sensor / Encoder Rev A3, Page 5/17 ELECTRICAL CHARACTERISTICS Operating conditions: VDD = 5 V ±10 % , Tj = -40 ... 125 °C, unless otherwise noted Item No. 604 605 606 607 701 702 703 704 801 802 803 804 805 Symbol tf() Ilk() Vc()hi Vc()lo Vt()hi Vt()lo Vt()hys Ipd() SR fhc() I() R()eda R()ada Parameter Fall time Leackage current Clamp voltage high Clamp voltage low Threshold voltage high Threshold voltage low Hysterese Pull-down current Slew Rate Cut off frequency Output current Input resistance DA-converter Output resistance DA-converter between pin B and pin C at pin A Vt()hys = Vt()hi - Vt()lo V() = 1 V...VDD 0.8 300 10 2 500 -1 6 8 100 1 10 30 50 Conditions Min. CL() = 50 pF NEN = high, V() = 0 ... VDD Vc()hi = V() - VDD, NEN = high, I() = 4 mA NEN = high, I() = -4 mA -5 0.3 -1.5 Typ. Max. 60 5 1.6 -0.3 2 ns µA V V V V mV µA V/µs kHz mA kΩ kΩ Unit Digital inputs: A, B, C, D Analog outputs: A, B, C, D psens psens psens ysens 0% 50% AArel twhi()/T center of chip Figure 1: Location of HALL sensors on die xdis hsens 0% 100% AArel 20 Figure 3: Definition of relative angular error ydis φdis center of chip 1 Figure 2: Position of die in TSSOP20 package iC-ML HALL Position Sensor / Encoder Rev A3, Page 6/17 OPERATING CONDITIONS: Logic Operating conditions: VDD = 5 V ±10 %, Tj = -40...125 °C, unless otherwise noted Input level low = 0...0.45 V, high = 2.4 V...VDD, timing according Fig. 4 Item No. Logic I001 ts(NEN) I002 tp(NEN) I003 tp(SIG1) I004 tp(SIG2) I005 tp(CFGx) Setup time NEN Delay time NENO Delay time SIG1 Delay time SIG2 Setup time at CFGx, x = 1..3 CLK : low → high, see Fig. 15 CLK : high → low, see Fig. 15 CL() = 50 pF, see Fig. 15 CL() = 50 pF, see Fig. 15 see Fig. 9 30 30 60 2 4 ns ns µs µs µs Symbol Parameter Conditions Min. Max. Unit V Input/Output 2.4V 2.0V 0.8V 0.45V t 1 0 Figure 4: Reference levels for delays iC-ML HALL Position Sensor / Encoder Rev A3, Page 7/17 The sensor principle In conjunction with a magnetic tape iC-ML can be used to create a complete linear encoder system. With a Hall sensor pitch of 1.28 mm, the iC-ML is taylored to work with a magnetic tape having a pole pitch of 2.56 mm (5.12 mm magnetic periode). At a resolution of 8 bit, the digital increment represents a linear distance of 20 µm. In the same way, pole wheels can also be used together with the iC-ML. Magnetic tapes (or pole wheels) with a smaller pitch than 2.56 mm can be used by skewing the iC-ML with respect to the tape direction and thus adjusting the projected sensor pitch to the tape pitch. iC-ML has four Hall sensors which are used pairwise to generate sine- and cosine signals. Each Hall sensor pair detects the magnetic tape at a lateral distance of half of a magnetic periode. From the difference of the hall voltages, each Hall sensor pair generates either the sine or the cosine signal. Due to the differential sensing, the resulting signal voltages are insensitve to external homgenious magnetic fields and pole with variations. From the physical principal, the Hall sensors are also insensitive to magnetic fields parallel to the chip surface. Arrangement and signal outputs Figure 5 shows the arrangement of the iC-ML to the magnetic tape. Both chip and magnetic tape are parallel aligned to each other. The coordinate system is defined in the way that the z-coordinate is perpendicularly to the surface of the magnetic tape and the x-direction lies in direction of travel. The four HALL sensors are located at the upper edge of the chip and should be centered to the magnetic tape for optimized magnetic sensing. Figure 6: Sensing of a pole wheel at the surface using iC-ML Figure 5: Arrangement of iC-ML to the magnetic tape Magnet wheels are scanned depending upon their direction of magnetization either on the surface or at the periphery. The sensing radius must be chosen accordingly to match the magnetic pitch to the sensor pitch. For further consideration, the reference position of the chip is selected in such a way that the x-position of the outmost left hall sensor coincides with the zero point of the magnetic tape, which is located at the center of an arbritrally chosen north pole of the magnetic tape. Then, as shown in figure 8, the corresponding output signals in the analog operation mode (S-Sensor) will be available as a function of the lateral shift xd . The electrical signals exhibit the same periodicity as the magnetic field of the magnetic tape, showing extremes at the poles (Vcos) or at the pole gaps (Vsin). iC-ML HALL Position Sensor / Encoder Rev A3, Page 8/17 this vector rotates counterclockwise (mathematically positive rotation), whereas if the tape is moved in positive x-direction (with respect to the chip), the vector rotates clockwise (mathematically negative rotation). Figure 7: Sensing of a pole wheel at the peripherie using iC-ML When the Vcos and Vsin signals are displayed as a Lissajou figure, a rotating vector is defined. If the chip is moved in positive x-direction with respect to the tape, Figure 8: Signal outputs Vsin und Vcos Programming the configuration iC-ML has 28 modes of operation (see tables on the following pages). After the device has been switched on or "woken up" from standby mode by a low signal at pin NEN the levels at the configuration inputs CFG1 to CFG3 are assessed. These three-level inputs can be connected to GND (low ), left open (open) or connected to VDD (high). For correct identification, a setup time of at least tp(CFGx) = 4 µs must be maintained between programming the configuration and activating the device. While the device is active changes in signal at the configuration inputs are ignored. If several iC-MLs are connected in series in chain operation (see the description of functions on page 12) it must be ensured that the NEN input of the devices is switched to low during the various clock cycles and that the programming default does thus not lie within the active phase of the devices. In standby all ports are switched to tristate, i.e. high impedance. Only in chain operation modes port D is active high so that the devices arranged further behind can also be deactivated. 4V VDD NEN iC-ML active CFGx iC-ML active td(VDD)on tp(CFGx) tp(CFGx) Figure 9: Programming the configuration iC-ML HALL Position Sensor / Encoder Rev A3, Page 9/17 Operating modes Mode NEN CFG1 CFG2 Analog low low S-Sensor low D-Sensor low open low D-Sensor low high low Linear output R-Sensor low low open low open open low high open low high open Chain-Mode low high AB-Chain low D-Chain low open high S-Chain low high high Incr. ABZ ABZ 8-1 low low low ABZ 8-0 low open low ABZ 7-1 low low open ABZ 7-0 low open open ABZ 6-1 low low high ABZ 6-0 low open high ABZ 8-1 low low low ABZ 8-0 low open low ABZ 7-1 low low open ABZ 7-0 low open open ABZ 6-1 low low high ABZ 6-0 low open high Incr. CLK CLK 8 low high low CLK 6 low high high DIR 8 low high low DIR 6 low high high Test (for iC-Haus use only) low high open Test Standby high x x 1 CFG3 low low low low low low high low low low open open open open open open high high high high high high open open high high open x Port A PSIN PSIN PSIN VTRI VTRI VSAW VSAW A PSIN/NSIN PSIN/VREF A A A A A A A A A A A A NCLKUP NCLKUP NCLK NCLK Port B VREF NSIN NSIN REFH REFH REFH REFH CLK CLK CLK B B B B B B B B B B B B NCLKDN NCLKDN DIR DIR Port C PCOS PCOS PCOS MSB MSB REFL REFL B PCOS/NCOS PCOS/GAIN Z Z Z Z Z Z Z Z Z Z Z Z NCLR NCLR NCLR NCLR Port D GAIN NCOS NCOS NERR GAIN NERR GAIN NENO NENO NENO NERR NERR NERR NERR NERR NERR NERR NERR NERR NERR NERR NERR NERR NERR NERR NERR Res. Comments PRM 8 8 8 8 8 8 8 7 7 6 6 8 8 7 7 6 6 8 6 8 6 AB=1 AB=0 AB=1 AB=0 AB=1 AB=0 AB=1, PRM AB=0, PRM AB=1, PRM AB=0, PRM AB=1, PRM AB=0, PRM Test TRI TRI TRI TRI1 In chain operation port D is active high so that the backend devices can also be deactivated. iC-ML HALL Position Sensor / Encoder Rev A3, Page 10/17 Analog modes of operation Mode Analog S-Sensor D-Sensor D-Sensor NEN CFG1 CFG2 CFG3 low low low low open high low low low low low low Port A PSIN PSIN PSIN Port B VREF NSIN NSIN Port C PCOS PCOS PCOS Port D GAIN NCOS NCOS Res. Comment PRM In the analog modes of operation the amplified Hall voltages are available at the output ports. The sine/ cosine output signals are controlled to have stable amplitudes of 1 V and referenced to a DC value equivalent to half of the supply voltage (VREF). Due to the internal signal conditioning unit, no special adjustment is required. An externally connected interpolator can be used if further trimming of the output signals is desired. 5 Signal GAIN allows conclusions to be drawn as to the operating point of the sensor. This is influenced by the amplitude of the magnetic field, the sensor supply voltage and temperature. The higher the GAIN potential, the greater the necessary amplification of the Hall voltages; the external magnetic field is smaller. Besides recording the direction of magnetization of the permanent magnet the distance between the magnet and sensor may also be assessed using the GAIN signal. If the gain is insufficient to boost the Hall voltages to 2 Vss the amplitude control reaches its upper limit and the output amplitude becomes smaller. The GAIN signal can be used to adjust the permanent magnet. If the central point of both the magnet and sensor iC-ML are the same the GAIN signal has no harmonics. A misaligned sensor must readjust the operating point depending on the angle; the GAIN signal varies in amplitude. To adjust the sensor to the magnetic tape this must be shifted along its y- and z-axis so that the GAIN signal has to readjust as little as possible. 4 PSIN NCOS Voltage [V] 3 VREF 2 NSIN PCOS 1 GAIN 0 0 100 200 300 400 500 600 700 Time [µs] Figure 10: Analog mode output signals after switching on the device S sensor mode After the device has been activated via NEN = low the sensor is set to its operating point. All signals are referenced to half the supply voltage (VREF). In S sensor mode this potential is available at port B. Ports A and C output the sine and cosine Hall voltages set to 2 Vss. The angle can be calculated from the relation of the sine voltage (difference in voltage PSIN to VREF) to the cosine voltage (difference in voltage PCOS to VREF). The device supplies an angle which remains non-ambiguous over a 360° rotation of the permanent magnet. D sensor mode In D sensor mode differential sine (pin A and pin B) and cosine (pin C and pin D) signals are supplied at the output; as opposed to S sensor mode inverted Hall signals are now also available at the ports. The advantage of this mode of operation is the doubled signal amplitude of the differential Hall voltages and the lack of dependence on reference voltage VREF. The angle is now calculated via the ratio of the difference between PSIN and NSIN and between PCOS and NCOS. D sensor mode is also available with a reduced power consumption (PRM or Power Reduced Mode). In this mode the Hall sensor is supplied with current less frequently, reducing the power consumption. Here it must be observed that the maximum rotating frequency also drops by a factor of 2. iC-ML HALL Position Sensor / Encoder Rev A3, Page 11/17 Resistor modes of operation Mode NEN CFG1 CFG2 CFG3 Linear output low open low R-Sensor low low open open low low high open low low high open high Port A VTRI VTRI VSAW VSAW Port B REFH REFH REFH REFH 5 Port C MSB MSB REFL REFL Port D NERR GAIN NERR GAIN Res. Comments 8 8 8 8 Voltage [V] Resistor modes of operation In R sensor mode the taps of an integrated resistive divider are selected depending on the angular position ("potentiometer replacement"). The value of the absolut angular position acts as a "wiper" and selects one of the 256 taps on the resistor chain. 4 REFH 3 VSAW 2 1 REFL 0 0 45 90 135 180 225 270 315 360 405 450 Angle [°] Figure 11: Potentiometer equivalents for resistor mode operations In modes with a sawtooth voltage VSAW at port A the angle is converted into a linear voltage which lies within thresholds REFH and REFL at ports B and C (see Figure 12). The integrated resistor chain is directly available at the ports so that thresholds REFH and REFL can also be reversed. Depending on the selected mode either a GAIN signal or a NERR error signal are present at port D to monitor the amplitude. If the amplitude is at least 70 %, NERR is high; should the amplitude sink to below 50 % of the set amplitude, NERR switches to active low. Modes of operation with a triangular voltage VTRI avoids the discontinuity at the zero angular position. Signal MSB can be used to differentiate between the first and second half rotation. The delta voltage is limited by thresholds REFH and GND. As in VSAW mode both GAIN and NERR signals are available. Figure 12: R-Sensor mode with sawtooth output voltage VSAW 5 4 REFH Voltage [V] 3 2 VTRI 1 MSB 0 0 45 90 135 180 225 270 315 360 405 450 Angle [°] Figure 13: R-Sensor mode with triangular output voltage VTRI iC-ML HALL Position Sensor / Encoder Rev A3, Page 12/17 AB chain, D chain and S chain modes Mode NEN Chain operation AB chain low D chain low S chain low CFG1 CFG2 CFG3 low open high high high high low low low Port A A PSIN/NSIN PSIN/VREF Port B CLK CLK CLK Port C B PCOS/NCOS PCOS/GAIN Port D NENO NENO NENO Res. Comments 8 CLK ML 0 CLK NEN(0) NEN NENO iC-ML ML 1 CLK NEN(1) NEN NENO iC-ML ML 2 CLK NEN(2) NEN NENO iC-ML NEN(3) A C A C A C A C Figure 14: Chain modes for iC-ML CLK ts(NEN) NEN(0) tp(NEN0) NEN(1) NEN(2) tp(SIG1) tp(SIG2) NEN(3) ts(NEN) TRISTATE TRISTATE TRISTATE TRISTATE TRISTATE TRISTATE TRISTATE A PSIN0 NSIN0 PSIN1 NSIN1 PSIN2 NSIN2 B PCOS0 NCOS0 PCOS1 NCOS1 PCOS2 NCOS2 ML 0 active ML 1 active ML 2 active Figure 15: Signal patterns in D chain mode TRISTATE iC-ML HALL Position Sensor / Encoder Rev A3, Page 13/17 In the various chain modes multiple iC-MLs can be arranged in a chain (see Figure 14) where all of the devices are connected by a shared CLK line (pin B). The NEN input is evaluated synchronously with the rising CLK edge. If the NEN input is switched to low, the device is active during the following CLK cycle(s). To allow the devices to be cascaded a delayed enable signal is generated at output pin NENO (pin D) with which the follow-on device can be activated. If the NEN input of the first device in the chain is reset to high, all devices in the chain are deactivated. Bus lines A (pin A) and C (pin C) are activated by tristate output stages which are high impedance when NEN is high and CLK is low and also following the second rising CLK edge. AB chain mode In AB chain mode two A/B digital incremental signals are generated at ports A and C. The two square-wave signals are phase shifted at either +90° or -90°, depending on the direction of rotation. Following a CLK pulse the next device in the chain is enabled. Here the falling CLK edge deactivates the current device (e.g. ML 1 in Figure 14) and activates the next device in the chain (ML 2) with a low signal at its NEN input. After a device has been activated the two bus lines A (port A) and B (port C) are first switched to low (see Figure 15). This is then followed by the incremental signals being output, starting at the zero position. In the event of error the bus lines remain low. D chain mode In D chain mode differential sine and cosine signals are generated at ports A and C. During the first clock pulse signals PSIN and PCOS are presented to the bus; during the second pulse signals NSIN and NCOS are on the bus (see Figure 15). In this mode each device is thus active for two clock pulses. During the first clock pulse the non-inverted sine (port A) and cosine (port C) signals are first presented to the bus, with the inverted signals following on the positive CLK edge during the second pulse. The falling CLK edge in the second clock pulse deactivates the current device and activates the following device in the chain with a low signal at its NEN input. S chain mode In S chain mode the non-inverted sine (port A) and cosine (port C) signals are presented to the bus during the first clock pulse, with the signals VREF (port A) and GAIN (port C) following on the positive CLK edge of the next pulse. Each device is thus active for two clock pulses. The falling CLK edge in the second clock pulse deactivates the current device and activates the following device in the chain with a low signal at its NEN input. The sine and cosine signals can be assessed using signal VREF. Signal GAIN (pin D) indicates iC-ML’s internal amplification (see Electrical Characteristics No. 207) and can be used to estimate the signal amplitude of the internal Hall sensor. The GAIN signal can also be used to adjust the rotary axis of the magnet to the center of the chip. NEN CLK NENO 5 Voltage [V] 4 3 2 1 0 0 100 200 A C 300 400 500 600 700 Time [µs] Figure 16: Bus signals and control signals in S chain mode iC-ML HALL Position Sensor / Encoder Rev A3, Page 14/17 Incremental ABZ modes Mode NEN Incr. ABZ ABZ 8-1 low ABZ 8-0 low ABZ 7-1 low ABZ 7-0 low ABZ 6-1 low ABZ 6-0 low ABZ 8-1 low ABZ 8-0 low ABZ 7-1 low ABZ 7-0 low ABZ 6-1 low ABZ 6-0 low CFG1 CFG2 CFG3 low open low open low open low open low open low open low low open open high high low low open open high high open open open open open open high high high high high high Port A A A A A A A A A A A A A Port B B B B B B B B B B B B B Port C Z Z Z Z Z Z Z Z Z Z Z Z Port D NERR NERR NERR NERR NERR NERR NERR NERR NERR NERR NERR NERR Res. Comments 8 8 7 7 6 6 8 8 7 7 6 6 AB=1 AB=0 AB=1 AB=0 AB=1 AB=0 AB=1, PRM AB=0, PRM AB=1, PRM AB=0, PRM AB=1, PRM AB=0, PRM iC-ML has an 8-bit sine/digital converter which can convert the sine/cosine sensor signals into a digitized angle. This angle is made available at the ports as an incremental value. Signal Z is always high when the angle is 0°; otherwise the signal is low. In all incremental modes of operation error signal NERR is available so that the plausibility of the counter value can be verified. At an amplitude which is less than 50 % of the set amplitude the error signal switches to low ; at an amplitude greater than 70 % the error signal is reset, i.e. set to high. Three different quantities regarding the number of edges per rotation of the magnet can be selected. These are a resolution of 6 bits (64 edges per rotation), 7 bits (128 edges) or 8 bits (256 edges). The conversion process is count-safe, i. e. the output of all edges up to the current angle position is guaranteed as long as the input frequency is less than the maximum possible rotation. All incremental resolutions also have a reduced power consumption mode(PRM). In this mode the Hall sensor is supplied with current intermittently, reducing the power consumption. Here it must be noted that the maximum input frequency drops by a factor of 2. A distinction can be made between the various modes of operation by studying the level of the AB signals on the Z pulse. In mode AB = 1 signals A and B are both high, as is Z at an angle of 0°. In mode AB = 0, however, both signals A and B are low when the Z signal is high. Firstly, the behavior of the sensor on switching on the device is described when the magnetic tape moves in the +x-direction (Figure 17). After switching on the sensor via NEN at low the sensor looks for its operating point. If 70 % of the set amplitude is achieved the error signal is reset. An error status during this phase is also signaled when signals A and B are high and Z low. In an error-free state Z is always high at zero position. iC-ML continues to search for its operating point by outputting the position of the external magnetic field at maximum count frequency via the incremental interface. Once the actual position has been obtained the device follows a changed input signal in real time. The edge frequency is thus 256 times the frequency of periodical movement of the magnetic tape at a set resolution of 8 bits. If a (rising) edge reaches B before a (rising) edge A, this means that the counter value has risen. If the edge reaches A before B, however, this indicates that the absolute value is lower. NEN NERR A B Z Time [us] Figure 17: Incremental signals after switching on the device, counting up iC-ML HALL Position Sensor / Encoder Rev A3, Page 15/17 angle between 0° and 180° the device counts up to the operating point; if this angle is between 180° and 360°, it first counts down. Starting when the device is switched on all edges are output until the absolute position is reached. The setup has to wait until a certain time has elapsed; this is dependent on the selected resolution and is the settling time of the sensor until the error bit is deleted plus the time needed to count up or down to the absolute position. With a resolution of 8 bits and an angle of 180°, for example, this period constitutes 100 µs sensor settling time plus 128 times 4 µs until the absolute position has been pinpointed. The absolute position is thus available after a maximum of 612 µs has elapsed. Time [us] NEN NERR A B Z Figure 18: Incremental signals after switching on the device, counting down Always starting at zero position, the device begins searching for the absolute position, locating it as quickly as possible. If this positon corresponds to an By way of example Figure 18 illustrates how the incremental interface behaves when the device first counts down to the absolute position and the magnetic tape then moves forwards, with the sensor following with the relevant sequence. The Z signal is synchronous with A and B at low. Incremental CLK modes Mode NEN CFG1 CFG2 Inkr. CLK CLK 8 low high low CLK 6 low high high DIR 8 low high low DIR 6 low high high CFG3 open open high high Port A NCLKUP NCLKUP NCLK NCLK Port B NCLKDN NCLKDN DIR DIR Port C NCLR NCLR NCLR NCLR Port D NERR NERR NERR NERR Res. Comments 8 6 8 6 CLK-INC mode In CLK-INC mode two different count signals are provided for the countup and countdown sequences. Depending on the direction of rotation either signal NCLKUP (pin A) is pulsed when the device counts up or signal NCLKDN (pin B) when the device counts down. In each case the remaining signal is high. The zero angle is displayed by the NCLR index track which can serve as an asynchronous reset for an external counter. Figure 19 demonstrates how iC-ML behaves in CLKINC mode, firstly when it counts up from the zero position and then, following a change in the direction of movement, when it counts back down to zero position. This mode permits the operation of external binary counter modules (such as 74HC/HCT193, for example), with signal NCLR (pin C) being used to reset the counter. With a rising edge of clock signal NCLKUP and a high at NCLKDN the counter status is incre- mented; with a rising edge of clock signal NCLKDN and a high at NCLKUP the counter status is decremented. Two 4-bit counters can be cascaded here to create a full 8-bit counter. NCLUP NCLDN NCLR Time [us] Figure 19: CLK-INC mode iC-ML HALL Position Sensor / Encoder Rev A3, Page 16/17 DATA INPUT VDD P0 CFG1 CFG2 CFG3 NEN NCLUP NCLDN CPU CPD NPL Q0 P1 P2 P3 TCU P0 CPU CPD NPL Q0 P1 P2 P3 TCU the value of the DIR signal. A low at DIR triggers a countup; a high causes the setup to count down. Figure 17 shows a countup sequence followed by a countdown sequence, both across the zero position. iC-ML NCLR NERR RESET GND 74HCT193 Q1 Q2 TCD MR 74HCT193 Q1 Q2 TCD MR Q3 Q3 CLK OUTPUT Figure 20: iC-ML with binary counter 74HCT193 DIR DIR-INC mode In DIR-INC mode a change in angle for both directions of rotation generates an output pulse for signal CLK (pin A). Signal DIR (pin B) gives the direction of rotation. This mode permits the operation of external binary counter modules (such as 74HC/HCT191, for example), with signal NCLR (pin C) being used to reset the external counter. With a rising edge at CLK the counter status is counted up or down, depending on NCLR Time [us] Figure 21: DIR-INC mode iC-Haus expressly reserves the right to change its products and/or specifications. An Infoletter gives details as to any amendments and additions made to the relevant current specifications on our internet website www.ichaus.de/infoletter; this letter is generated automatically and shall be sent to registered users by email. Copying – even as an excerpt – is only permitted with iC-Haus approval in writing and precise reference to source. iC-Haus does not warrant the accuracy, completeness or timeliness of the specification on this site and does not assume liability for any errors or omissions in the materials. The data specified is intended solely for the purpose of product description. No representations or warranties, either express or implied, of merchantability, fitness for a particular purpose or of any other nature are made hereunder with respect to information/specification or the products to which information refers and no guarantee with respect to compliance to the intended use is given. In particular, this also applies to the stated possible applications or areas of applications of the product. iC-Haus conveys no patent, copyright, mask work right or other trade mark right to this product. iC-Haus assumes no liability for any patent and/or other trade mark rights of a third party resulting from processing or handling of the product and/or any other use of the product. As a general rule our developments, IPs, principle circuitry and range of Integrated Circuits are suitable and specifically designed for appropriate use in technical applications, such as in devices, systems and any kind of technical equipment, in so far as they do not infringe existing patent rights. In principle the range of use is limitless in a technical sense and refers to the products listed in the inventory of goods compiled for the 2008 and following export trade statistics issued annually by the Bureau of Statistics in Wiesbaden, for example, or to any product in the product catalogue published for the 2007 and following exhibitions in Hanover (Hannover-Messe). We understand suitable application of our published designs to be state-of-the-art technology which can no longer be classed as inventive under the stipulations of patent law. Our explicit application notes are to be treated only as mere examples of the many possible and extremely advantageous uses our products can be put to. iC-ML HALL Position Sensor / Encoder Rev A3, Page 17/17 ORDERING INFORMATION Type iC-ML iC-ML evaluation board Package TSSOP20 Order Designation iC-ML TSSOP20 iC-ML EVAL ML1D For technical support, information about prices and terms of delivery please contact: iC-Haus GmbH Am Kuemmerling 18 D-55294 Bodenheim GERMANY Tel.: +49 (61 35) 92 92-0 Fax: +49 (61 35) 92 92-192 Web: http://www.ichaus.com E-Mail: sales@ichaus.com Appointed local distributors: http://www.ichaus.com/sales_partners