MA100GQ-P

Angular Sensor for 3-Phase Brushless Motor Commutation with Side-Shaft Positioning Capability MagAlpha MA100 Key features U V W signals for block commutation Built-in linearization for side-shaft mounting Adjustable zero 500 kHz refresh rate Ultra low latency: 3 µs Serial interface for settings 8.5 mA supply current QFN-16 3x3mm Package General Description The MagAlpha MA100 is a magnetic sensor designed to replace the 3 Hall switches for commutation in 3phase brushless dc motors. The IC detects the absolute angular position of a permanent magnet, typically a diametrically magnetized cylinder attached to the rotor. The MagAlpha is an extremely fast acquisition and processing sensor, allowing accurate angle measurement at speeds from 0 to 120’000 RPM. Since the measurement is spatially confined, the user has flexibility in terms of magnet shapes and configurations. This can help relaxing mechanical tolerances and, in case the end of shaft position is not available, the MagAlpha 100 can also operate away from the axis of rotation (“side-shaft” mounting). Figure 1: Functional Block Diagram Monolithic Power Systems, Inc. | Gland, Switzerland | Tel: +41 22 364 63 50 | euroinfo@monolithicpower.com | www.sensimatech.com MPS Proprietary Information. Unauthorized Photocopy and Duplication Prohibited. © 2014 Monolithic Power Systems. All Rights Reserved. MA700 Rev 1.0 September 2014 1 MA100 Angular Sensor for 3-Phase Brushless Motor Commutation with Side-Shaft Positioning Capability 1. Specifications TABLE 1 OPERATING CONDITIONS Parameters Symbol Min Typ Max Unit Supply voltage VDD 3.0 3.3 3.6 V Supply current Isup 6.8 8.5 9.8 mA Vflash 3.6 3.8 V Iflash 50 100 mA Operating temperature Top -40 125 °C Applied magnetic field B 50 200 mT Supply voltage for OTP flashing Supply current for OTP flashing (1) (1) 80 See section 11 for more details about the supply circuit for OTP flashing. TABLE 2 SENSOR OUTPUT SPECIFICATIONS Measurement conditions: VDD = 3.3 V, 50 mT < B < 100 mT, Temp = -40 . +125°C, unless otherwise noted Parameters Min Typ 2 3 ms +/- 0.7 +/- 1.5 +/-2.5 deg Temperature induced +/-0.005 +/-0.008 +/-0.05 deg/°C Magnetic field induced -0.005 -0.01 -0.025 deg/mT Voltage supply induced 0.0007 0.001 0.005 deg/mV Power up time INL Max Unit Remark Output drift Absolute output - serial Data output length Refresh rate 8 8 bit 500 520 550 kHz Latency 2 3 4 µs Resolution (3 noise level) 8 8 bit Digital I/O Threshold voltage High 1.75 V Threshold voltage Low 1.05 V Rising edge slew rate 0.7 V/ns CL = 50 pF Falling edge slew rate 0.7 V/ns CL = 50 pF Monolithic Power Systems, Inc. | Gland, Switzerland | Tel: +41 22 364 63 50 | euroinfo@monolithicpower.com | www.sensimatech.com MPS Proprietary Information. Unauthorized Photocopy and Duplication Prohibited. © 2014 Monolithic Power Systems. All Rights Reserved. MA700 Rev 1.0 September 2014 2 MA100 Angular Sensor for 3-Phase Brushless Motor Commutation with Side-Shaft Positioning Capability 2. Timing of the Serial Interface The data link is a 4-wire serial bus, compatible to the Serial Peripheral Interface (SPI) convention shown in Table 3 and Table 4. The MagAlpha sensor operates as a slave. During one transmission a 16-bit word can be simultaneously sent to the sensor (MOSI pin) and received from the sensor (MISO pin).See section 10 “Output Signals” for details. Figure 2: SPI Timing Diagram TABLE 3 SPI SPECIFICATION TABLE 4 SPI STANDARD SCLK idle state High CPOL 1 SCLK readout edge Rising CPHA 1 CS idle state High MODE 3 Data order MSB first DORD 0 TABLE 5 SPI TIMING Parameter Description Min Max tidle Time between two subsequent transmissions 20 ns tcsL Time between CS falling edge and SCLK falling edge 25 ns tsclk SCLK period 40 ns tsclkL Low level of SCLK signal 20 ns tsclkH High level of SCLK signal 20 ns tcsH Time between SCLK rising edge and CS rising edge 25 ns tMOSI Data input valid to SCLK reading edge 15 ns tMISO SCLK setting edge to data output valid 15 Unit ns Monolithic Power Systems, Inc. | Gland, Switzerland | Tel: +41 22 364 63 50 | euroinfo@monolithicpower.com | www.sensimatech.com MPS Proprietary Information. Unauthorized Photocopy and Duplication Prohibited. © 2014 Monolithic Power Systems. All Rights Reserved. MA700 Rev 1.0 September 2014 3 MA100 Angular Sensor for 3-Phase Brushless Motor Commutation with Side-Shaft Positioning Capability 3. Registers TABLE 6 REGISTER MAP Register address No Hex Bin 3 0x3 0011 BCT(7:0) 4 0x4 0100 Z(11:4) 5 0x5 0101 0 0 ETY ETX 9 0x9 1001 - - F5 F4 Bit 7 MSB Bit 6 Bit 5 Bit 4 Bit 3 Bit 2 Bit 1 Bit 0 LSB - - 0 F3 - TABLE 7 PROGRAMMING PARAMETERS Symbol Number of bit BCT 8 Z 12 Enable Trimming X ETX 1 Enable Trimming Y ETY 1 Fn 1 Parameters Bias Current Trimming Zero setting Flash register n Brief description For side-shaft configuration: reduce the Hall device bias current of X- and/or Y-axis Set the zero position When enabled, the X-axis bias current is trimmed by the quantity BCT When enabled, the Y-axis bias current is trimmed by the quantity BCT Flash the content of register number n See table 9 11 10 10 Monolithic Power Systems, Inc. | Gland, Switzerland | Tel: +41 22 364 63 50 | euroinfo@monolithicpower.com | www.sensimatech.com MPS Proprietary Information. Unauthorized Photocopy and Duplication Prohibited. © 2014 Monolithic Power Systems. All Rights Reserved. MA700 Rev 1.0 September 2014 4 MA100 Angular Sensor for 3-Phase Brushless Motor Commutation with Side-Shaft Positioning Capability 4. Pin Configuration TABLE 8 PIN FUNCTIONS No Figure 3: Top view QFN-16 Name Function 1 V 2 N/C V (Incremental output) - 3 N/C - 4 MOSI Data in (Serial) 5 CS Chip Select (Serial) 6 N/C - 7 MISO Data out (Serial) 8 GND Ground 9 W 10 N/C - 11 N/C - 12 SCLK Clock (Serial) 13 VDD 3.3 V supply 14 N/C - 15 U 16 VFLASH W (Incremental output) U (Incremental output) 3.6 V supply for OTP flashing Monolithic Power Systems, Inc. | Gland, Switzerland | Tel: +41 22 364 63 50 | euroinfo@monolithicpower.com | www.sensimatech.com MPS Proprietary Information. Unauthorized Photocopy and Duplication Prohibited. © 2014 Monolithic Power Systems. All Rights Reserved. MA700 Rev 1.0 September 2014 5 MA100 Angular Sensor for 3-Phase Brushless Motor Commutation with Side-Shaft Positioning Capability 5. Sensor – Magnet Mounting The sensitive volume of the MA100 is confined in a region less than 100 µm wide and consists of multiple integrated Hall devices. This volume is located, with a precision of 50 m in the center of the QFN package, both horizontally and vertically. The sensor detects the angle of the magnetic field projected in a plane parallel to the package upper surface. It means that the only magnetic field that matters is the in-plane component (X and Y components) in the package middle point. Table 2). The straightforward solution is to place the MA100 sensor on the rotation axis of a permanent magnet for instance a cylinder diametrically magnetized (see Figure 4). Figure 5: Side-Shaft Mounting Figure 4: End-of-Shaft Mounting This detection mode gives flexibility for the design of an angular encoder: all the sensor needs is that the magnetic vector lies essentially within the sensor plane and that its amplitude is comprised between 50 and 200 mT. Note that the MA100 does work with smaller than 50 mT fields, but the linearity and resolution performance may deviate from the specifications (see When the end-of-shaft position is not available the sensor can be positioned away from the rotation axis of a cylinder or ring magnet (see Figure 5). In this case the magnetic field angle is not directly proportional to the mechanical angle anymore. The MA100 can be adjusted to compensate this effect and recover the linear relation between the mechanical angle and the sensor output. With multiple pole pairs, the MA100 will indicate multiple rotations for each mechanical turn. 6. Power Supply Decoupling For most applications, a single 100 nF bypass capacitor placed close to the supply pins sufficiently decouples the MA100 from noise of the power supply. If better decoupling is required, a larger capacitor (10 µF) can be added in parallel with the 100 nF, and/or a resistor (10 ) can be added between the supply line and the capacitor node. In any case, make sure that the connection between the MA100 ground and the power supply ground has low impedance, in order to avoid noise transmitted from the ground. VFLASH needs to be supplied only when flashing the memory. Otherwise the VFLASH pin can remain unconnected or grounded (see Figure 6). Figure 6: Connection for Supply Decoupling Monolithic Power Systems, Inc. | Gland, Switzerland | Tel: +41 22 364 63 50 | euroinfo@monolithicpower.com | www.sensimatech.com MPS Proprietary Information. Unauthorized Photocopy and Duplication Prohibited. © 2014 Monolithic Power Systems. All Rights Reserved. MA700 Rev 1.0 September 2014 6 MA100 Angular Sensor for 3-Phase Brushless Motor Commutation with Side-Shaft Positioning Capability 7. Sensor Front-End The magnetic field is detected with integrated Hall devices located in the package center. The angle is measured using the spinaxis method, which directly digitizes the direction of the field without any ATAN computation or any feedback loop based circuit (interpolators, etc.). The spinaxis method is based on phase detection. It requires a sensitive circuitry generating a sinusoidal signal whose phase represents the angle of the magnetic field. The angle is then retrieved by a time-todigital converter, which counts the time between the zero crossing of the sinusoidal signal and the edge of a constant waveform (see Figure 7). The digitized time is the front-end output. Figure 8: Hall Devices Biasing Diagram In case the MA100 gets mounted in side-shaft configuration, the relation between the field angle and the mechanical angle is not directly linear anymore. This effect is related to the fact that the tangential magnetic field is usually smaller than the radial field. We define the field ratio as: , Figure 7: Phase Detection Method. Top: Sine Waveform. Bottom: Clock of Time-to-Digital Converter. where , respectively , is the maximum radial, respectively tangential, magnetic field (see Figure 9). Looking further down the signal conditioning chain, it is crucial that the signal conditioning does not add unwanted phase shifts. For this purpose the MagAlpha incorporates an architecture where these shifts are automatically compensated, resulting in the stability displayed in Table 2. In short, the front-end delivers in a straightforward and open loop manner a digital number proportional to the angle of the magnetic field at the rate of 500 kHz. Side-shaft The default current biasing of the Hall devices can be adjusted by programming in order to accommodate low field or compensate non-linearities inherent to sideshaft configurations. Figure 9: Side-Shaft Field The ratio k depends on the magnet geometry and the distance to the sensor. The X-axis or the Y-axis bias current can be reduced in order to recover an equal Hall signal for all angles and therefore suppress the non-linearity. The current reduction is set by the parameter Bias Current Monolithic Power Systems, Inc. | Gland, Switzerland | Tel: +41 22 364 63 50 | euroinfo@monolithicpower.com | www.sensimatech.com MPS Proprietary Information. Unauthorized Photocopy and Duplication Prohibited. © 2014 Monolithic Power Systems. All Rights Reserved. MA700 Rev 1.0 September 2014 7 MA100 Angular Sensor for 3-Phase Brushless Motor Commutation with Side-Shaft Positioning Capability Trimming BCT (7:0), which is an integer from 0 to 255. For an optimum compensation the radial axis should be reduced by the quantity: TABLE 9 EXAMPLE OF OPTIMUM BCT SETTING BCT(7:0) Zero setting The zero position of the MagAlpha, , can be programmed with 8 bit of resolution. The angle streamed out, , is given by: , Magnet ratio k 0 1 1 1.003 … … 128 1.50 … … 255 3.00 From the dot printed on the package it is possible to know whether the radial field is detected by the sensor X or Y component (see Figure 10). where is the raw angle, out of the front-end. The parameter Z(7:0), which is 0 by default, determines (table 11). This setting is valid for all output formats: SPI and UVW. TABLE 11 ZERO POSITION Z(11:0) Zero position 0 0 1 1.41 … … 255 358.59 (deg) Figure 10: Package Top View with X and Y Axes First the user must determine which axis needs to be reduced (see the qualitative field distribution around a ring in Figure 9). For instance, with the arrangement depicted in the figure 10, the X-axis should be reduced. Then the parameter ETX or ETY can be set. Note that if both ETX and ETY are set to 1 the current bias will be reduced in both directions the same way, i.e. without side-shaft correction. TABLE 10 ETX AND ETY ETX Enable trimming the X axis 0 Disabled 1 Enabled ETY Enable trimming the Y axis 0 Disabled 1 Enabled Monolithic Power Systems, Inc. | Gland, Switzerland | Tel: +41 22 364 63 50 | euroinfo@monolithicpower.com | www.sensimatech.com MPS Proprietary Information. Unauthorized Photocopy and Duplication Prohibited. © 2014 Monolithic Power Systems. All Rights Reserved. MA700 Rev 1.0 September 2014 8 MA100 Angular Sensor for 3-Phase Brushless Motor Commutation with Side-Shaft Positioning Capability 8. Programming the MA100 The MA100 incorporates 3 programmable registers. Each register has 8 bit of memory. When the MA100 is powered up, each of these 3 x 8 bit of memory are set to zero, unless the register was previously stored in the One-Time-Programmable (OTP) memory. It means that during startup, the content of the OTP memory is copied to the registers. Once flashed the register content cannot be modified anymore. In order to set the content of a register, the user must send a digital stream composed of the 4-bit REGISTER WRITE command (0010), followed by a 4-bit register address and the 8-bit value to be sent to the register. The data stream, sent through the MOSI wire, is therefore 16 bits long: command 0 0 1 0 reg. address MSB value LSB Once the command is sent, it will immediately be effective and will affect the next data sent from the MagAlpha. Read back the register content It might be helpful to check the content of a register, for instance to verify that the programming was successful. The user must send the REGISTER READ 9. command: 0001, then the 4-bit address of the register under test. The last 8-bit of the stream will be ignored. The user can send for instance 0000 0000: command 0 0 0 1 reg. address x x x x value LSB 0 0 0 0 0 0 0 0 MSB The MagAlpha response is within the same transmission. In the first byte (simultaneous to the 4-bit READ command and the 4-bit address), the MagAlpha sends the 8 bits of the measured angle A(7:0). The second byte is the content of the register under test. After this transmission the MagAlpha will continue delivering the usual angles A(7:0). Example To check the content of the register 4 (0100), which contains the zero setting, send the data: command 0 0 0 1 reg. address 0 1 0 0 value LSB 0 0 0 0 0 0 0 0 MSB Simultaneously the MagAlpha replies: Angle out A(7:4) A(3:0) MSB value Z(7:0) LSB Output Signals The raw data coming out of the conditioning blocks is an absolute angle, between 0 and 360 deg. This angle is coded on 16 bits, depending on the value of AF. The absolute output is sent out digitally as serial data. The other outputs, ABZ or UVW, are constructed from the absolute angles. Absolute - Serial The bit order of the transmitted data is MSB first, LSB last. The timing requirements are indicated in section 3. Every 2µs a new data is transferred into the output buffer. The master device connected to the MagAlpha triggers the reading by pulling the CS down. When a falling edge of the CS signal occurs, the data remains in the output buffer until the CS signal returns to logic 1. As the CS is low, the master can read the data by sending clock pulses with a maximum frequency of 25 MHz. There is not any minimum frequency or timeout. See Figure 11 for a simple reading of 8-bit data. Monolithic Power Systems, Inc. | Gland, Switzerland | Tel: +41 22 364 63 50 | euroinfo@monolithicpower.com | www.sensimatech.com MPS Proprietary Information. Unauthorized Photocopy and Duplication Prohibited. © 2014 Monolithic Power Systems. All Rights Reserved. MA700 Rev 1.0 September 2014 9 MA100 Angular Sensor for 3-Phase Brushless Motor Commutation with Side-Shaft Positioning Capability Block Commutation - UVW Figure 11: Timing diagram for simple SPI readout The UVW output emulates the three Hall switches usually used for the block commutation of 3-phases electric motor. The three logic signals have a duty cycle of ½ and are shifted by 60 deg relative to each other (see Figure 12). A full reading requires 16 clock pulses. The MA100 delivers: MSB LSB A(8:0) In case the user needs less resolution, since the MSB is sent first, he can read the angle by sending less than 8 pulses. If the master triggers the reading faster than the refresh rate the MagAlpha may send several times the same data point. Figure 12: UVW Output during Rotation Monolithic Power Systems, Inc. | Gland, Switzerland | Tel: +41 22 364 63 50 | euroinfo@monolithicpower.com | www.sensimatech.com MPS Proprietary Information. Unauthorized Photocopy and Duplication Prohibited. © 2014 Monolithic Power Systems. All Rights Reserved. MA700 Rev 1.0 September 2014 10 MA100 Angular Sensor for 3-Phase Brushless Motor Commutation with Side-Shaft Positioning Capability 10. OTP Programming The One-Time-Programmable (OTP) memory can permanently store the content of the programmable registers. The OTP memory is made of poly-silicon fuses. By activating the “flash” command the content of the entire register will be stored in the OTP memory. The flash command consists in setting some bits (named Fn, where n is the register number) in the register 9. When the bit Fn is set, the register n is stored permanently. Important: the user can flash only one register at the time. It is possible to operate the MagAlpha without flashing the registers. - In the register 9, set the bit corresponding to the register to be flashed. Untie the VFLASH pin Then switch off and on and check by reading back the register content. Example: set & flash the zero position at 50 deg Note: permanently storing the zero position requires to burn two registers, the 4 and the 5. 1. Convert into binary: within a resolution of 8 bits, 50 deg is the binary number 00100011 (49.22 deg). 2. Store the value (00100011) of the zero position into register 4: command 0 0 1 0 3. Figure 13: Circuit for Flashing The burning of the fuses during the flash process is irreversible: once a register is flashed the default values at power up will always be the same. After flashing the registers content cannot be modified anymore (see Figure 13). Flashing procedure Prior to flashing, it is recommended to test the MagAlpha with the new settings and verify the performance of the sensor. Once satisfied, the user can proceed with the flashing: - Send the parameter to the register, and read back for verification. Tie the VFLASH pin to 3.6 V. Note: it is possible to supply both VDD and VFLASH with the same 3.6 V source. reg. address 0 1 0 0 value LSB 0 0 1 0 0 0 1 1 MSB Read back the register 4 command 0 0 0 1 reg. address 0 1 0 0 value LSB 0 0 0 0 0 0 0 0 MSB If the programming was correct the MagAlpha replies with the register 4 content: Angle out A(7:4) A(3:0) value LSB 0 0 1 0 0 0 1 1 MSB 4. Connect the VFLASH pin to 3.6 V 5. Flash register 4: command 0 0 1 0 reg. address 1 0 0 1 value LSB 0 0 0 1 0 0 0 0 MSB 6. Disconnect the VFLASH pin from 3.6 V. 7. Turn the MagAlpha off and on, and read back the register 4 to verify that the flashing was successfully accomplished (steps 3). Monolithic Power Systems, Inc. | Gland, Switzerland | Tel: +41 22 364 63 50 | euroinfo@monolithicpower.com | www.sensimatech.com MPS Proprietary Information. Unauthorized Photocopy and Duplication Prohibited. © 2014 Monolithic Power Systems. All Rights Reserved. MA700 Rev 1.0 September 2014 11 MA100 Angular Sensor for 3-Phase Brushless Motor Commutation with Side-Shaft Positioning Capability 11. Typical Characteristics Measurement conditions: VDD = 3.3 V, Temp = 25°C, unless otherwise noted (see Figure 14). Figure 14: Error Curve at Different Magnetic Fields. The INL is the Maximum Value of this Curve. Monolithic Power Systems, Inc. | Gland, Switzerland | Tel: +41 22 364 63 50 | euroinfo@monolithicpower.com | www.sensimatech.com MPS Proprietary Information. Unauthorized Photocopy and Duplication Prohibited. © 2014 Monolithic Power Systems. All Rights Reserved. MA700 Rev 1.0 September 2014 12 MA100 Angular Sensor for 3-Phase Brushless Motor Commutation with Side-Shaft Positioning Capability 12. Package Dimensions Package: Plastic Quad Flatpack No-lead QFN-16 3x3 mm NOTES: 1. All dimensions are in mm 2. Package dimensions does not include mold flash, protrusions, burrs or metal smearing 3. Coplanarity shall be 0.08 4. Compliant with JEDEC MO-220 Monolithic Power Systems, Inc. | Gland, Switzerland | Tel: +41 22 364 63 50 | euroinfo@monolithicpower.com | www.sensimatech.com MPS Proprietary Information. Unauthorized Photocopy and Duplication Prohibited. © 2014 Monolithic Power Systems. All Rights Reserved. MA700 Rev 1.0 September 2014 13 MA100 Angular Sensor for 3-Phase Brushless Motor Commutation with Side-Shaft Positioning Capability 13. Ordering Information Part Number Package Free Air Temperature (TA) MA100GQ QFN 3x3mm -40° to 125° * For Tape & Reel, add suffix –Z (e.g. MA100GQ–Z). Appendix A: Definitions Resolution (3 noise level) The smallest angle increment distinguishable from the noise. Here the resolution is defined as 3 times , the standard deviation in degrees, taken over 1000 data points at a constant position. The resolution in bits is obtained with: 6 . Refresh rate Rate at which new data points are stored in the output buffer. Latency The time between the data ready at the output and the instant at which the shaft passes that position. The lag in degrees is , where is the angular velocity in deg/s. Power up time Starting at power up, time until the sensor delivers valid data. Integral Non-Linearity (INL) Maximum deviation between the sensor output and the best line fit. Monolithic Power Systems, Inc. | Gland, Switzerland | Tel: +41 22 364 63 50 | euroinfo@monolithicpower.com | www.sensimatech.com MPS Proprietary Information. Unauthorized Photocopy and Duplication Prohibited. © 2014 Monolithic Power Systems. All Rights Reserved. MA700 Rev 1.0 September 2014 14 MA100 Angular Sensor for 3-Phase Brushless Motor Commutation with Side-Shaft Positioning Capability 400 sensor out (deg) 350 300 lag 250 ideal sensor output 200 150 INL 100 0 sensor out best straight fit resolution ( ± 3 ) 50 0 100 200 300 400 500 600 700 rotor position (deg) Figure A1: Absolute Angle Errors Overall reproducibility Maximum variation between two readings, successive or not, of the same shaft position at a fixed magnetic field over the complete temperature range. Monolithic Power Systems, Inc. Switzerland www.sensimatech.com euroinfo@monolithicpower.com  +41 22 364 63 50 The information provided by Monolithic Power Systems, Inc. in this document is believed to be correct. However MPS reserves the right, without further notice, (i) to change the product specification and/or the information in this document and (ii) to improve reliability, functions and design of the product and (iii) to discontinue or limit production or distribution of any product version. Monolithic Power Systems, Inc. does not assume any liability arising out of any application or use of any product or information, including without limitation consequential or incidental damages. All operating parameters must be validated for each customer's application by customer's technical experts. Recommended parameters can and do vary in different applications. Devices sold by MPS are covered by patents and patent applications. By this publication MPS does not assume responsibility for patent infringements or other rights of third parties which may result from its use. Monolithic Power Systems, Inc. | Gland, Switzerland | Tel: +41 22 364 63 50 | euroinfo@monolithicpower.com | www.sensimatech.com MPS Proprietary Information. Unauthorized Photocopy and Duplication Prohibited. © 2014 Monolithic Power Systems. All Rights Reserved. MA700 Rev 1.0 September 2014 15