Features • • • • • • 2-Phase 1 A Stepping Motor Driver Compensated Half Step Operation Chopper Current Control Unidirectional Single Wire Bus Interface with Error Feedback Intelligent Travel Operation Control Referencing by Extending or Retracting Application • Dynamic Headlamp Adjustment Benefits • • • • Error Recognition with Feedback Short Circuit Protected Outputs Overtemperature Warning and Shut Off Supply Voltage Supervision Intelligent Stepper Motor Driver ATA6830 Electrostatic sensitive device
Voltage Regulator VSS Supply Monitor COS Oscillator VDD Temperature Monitor RSET Biasing AGND Figure 1. Block Diagram BUS UART VBAT1A VBAT1B Command Interpreter SM1B SRA Driver Logic Driver Logic Cruising Service Control SM1A SRB SM2A SM2B VBAT2A VBAT2B Test Logic ATA6830 Pin Configuration n.c. COS RSET AGND VSS VDD BUS Figure 2. Pinning HP-VFQFP-N28 28 27 26 25 24 23 22 VBAT1A 1 21 VBAT1B n.c. 2 20 n.c.
ATA6830 Pin Description Pin Symbol Function 1 VBAT1A Battery voltage 2 n.c. Not connected 3 SM1A 4 SRA 5 SM2A 6 n.c. 7 VBAT2A Battery voltage 8 n.c.
Functional Description Analog Blocks Figure 3. Analog Blocks VBAT VDD Supply Bias Oscillator Bias Generator Bandgap Voltage Regulator Voltage Supervisor Temperature Supervisor Voltage Levels Temperature Levels Clock Reset COS RSET AGND VSS The circuit contains an integrated 5 V regulator to supply the internal logic and analog circuit blocks. The regulator uses an adjusted bandgap as voltage reference.
ATA6830 Digital Blocks Figure 4. Digital Blocks Clk Step Time Memory Reset Voltage Levels Maximum Step Time Temperature Signals New Step Time Actual Step Time Error Signals UART BUS VREF shiftclk Clock Recovery bitstream Bitstream Recovery rxd reference run Data Recognition & Parity-Check new position Cruise Control Stepper Motor Control Desired Position Instantaneous Position Error Timer Error Signals Figure 4 shows all digital blocks of the circuit.
Stepping Motor Driver Figure 5. Stepping Motor Driver Stepper Motor Control Driver Logic Error Signals VBAT SM1x SM2x Temperature Shutdown Temp. Shutdown Temperature Warning Temp. Warning Clk SRx Vref Reset Shunt Figure 5 shows the diagram of one H-bridge driver stage. It consists of two NMOS and two PMOS power transistors. An external shunt is used for measuring the current flowing through the motor coil.
ATA6830 Figure 6. Synchronization Sequence SYNCHRONIZATION PATTERN PARITY BIT START BIT START BIT PARITY BIT STOP BIT STOP BIT Between two commands a pause has to be included. This is necessary for a clear recogition of a new message frame (command). Figure 7 shows the timing diagram of two commands. Figure 7. Message Frame and Space MESSAGE FRAME HIGH BYTE SPACE LOW BYTE Every command consists of 16 bits. They will be sent with two bytes. Figure 8 shows the message frame.
Bus Commands There are different commands for controlling the stepping motor. Table 1 shows a list of all implemented commands and their meanings. The first command, the synchronization sequence, is described above. The second group of commands are the reference commands. A reference run command causes the stepping motor to make an initial run. It is used to establish a defined start position for the following position commands. The way the reference run is executed will be described later.
ATA6830 Power-up Sequence After power-up the circuit has to be synchronized and a reference run has to be executed before a position command can be carried out. Figure 9 shows a timing diagram on how the necessary sequences follow each other. Figure 9. Power-up Sequence POWER UP SYNCHRONIZATION SEQUENCE REFERENCE RUN SEQUENCE POSITION 1 POSITION 2 1 2 4 1 2 10 MESSAGE FRAME The first sequence is the synchronization sequence.
Figure 10.
ATA6830 Reference Run In normal operation, new position commands are transmitted as absolute values. To drive the stepping motor to these absolute positions, the circuit has to know the motor’s zero position. Therefore, the stepping motor has to perform a reference run after each power-up in which it is extended or retracted to its limit stop. Before the execution of the reference run, the motor is supplied with hold current.
Figure 11. Cruise Control frequency present frequency minimum frequency (300 Hz) present position nominal position time t+1 nominal positon time t position Table 3.
ATA6830 If the chip temperature exceeds the overtemperature warning threshold, the step speed is reduced to 300 Hz. If the chip temperature rises further the output driver is shut off. Table 4. Maximum Step Frequency Step Operation VBAT Maximum Step Frequency at Rising Voltage Maximum Step Frequency (VBAT once > 10.5 V) <9V No operation No operation 9 V to 9.5 V No operation 300 Hz (3.33 ms) 9.5 V to 10 V No operation 500 Hz (2.03 ms) 10 V to 10.5 V No operation 680 Hz (1,47 ms) 10.
Figure 13. Chopper Current Control turn on signal Imax coil current flyback comparator shunt resistor voltage blanking time Figure 14. Current Flow in Halfbridge ON OFF ON ON OFF ON OFF OFF a) Exception Handling b) During operation, different exceptional states or errors can arise to which the circuit must correspondingly react. These are described below: • Supply voltage below 9 V Travel operation is suspended for the duration of the undervoltage. The output current will be set to zero.
ATA6830 Travel operation is suspended when overtemperature is detected. An error signal is sent to the bus master via the bus. Operation can only restart after the supply voltage is shut off. • Interruption of a stepping motor winding The motor windings are only checked for interruption when supplied with hold current, not during drive operation. The corresponding output is shut off. The other coil winding is supplied with hold current. An error signal is sent.
Thermal Resistance Parameters Symbol Value Unit Thermal resistance junction-case RthJC 5 K/W Thermal resistance junction-ambient RthJA 35 K/W Symbol Value Unit Operating Range Parameters Power supply range Operating temperature range VBAT 7 to 20 V Top -40 to +105 °C Electrical Characteristics No. 1 1.1 1.2 Parameters Test Conditions Pin Symbol Supply current VBAT = 14 V (no motor current) 1, 7, 15, 21 I_total Supply voltage Normal operation 1, 7, 15, 21 VBATsup 7.
ATA6830 Electrical Characteristics (Continued) No. 5.2 5.3 5.4 5.5 5.6 5.7 5.8 5.9 5.10 5.11 6 Parameters Test Conditions Pin Symbol Min. Output current Output stage off 3, 5, 17, 20 ILEAK Output current Hold mode 3, 5, 17, 20 VSHUNT18 40 Output current Test mode 3, 5, 17, 20 VSHUNT99 Output current Normal mode 3, 5, 17, 20 Output current Normal mode (T <0°C) Output current Max.
Electrical Characteristics (Continued) No. Parameters Test Conditions Pin Symbol Min. Typ. Max. Unit Type* 6.13 Threshold voltage 11.0 V comparator, rising edge 1, 7, 15, 21 V11_UP 10.8 11.1 11.4 V A 6.14 Threshold voltage 11.0 V comparator, falling edge 1, 7, 15, 21 V11_DOWN 10.6 10.9 11.2 V A 6.15 Hysteresis 11.0 V comparator 1, 7, 15, 21 V11_HYS 60 200 340 mV A 6.16 Threshold voltage 20.0 V comparator, rising edge 1, 7, 15, 21 V20_UP 19.7 20.2 20.7 V A 6.
ATA6830 Electrical Characteristics (Continued) No. 7.2 7.3 7.4 8 8.1 8.2 9 Parameters Test Conditions Pin Symbol Min. Delay time 2 following commands 22 TD 5 Pause time Between high and low byte 22 TP Clamping time Bus error clamping 22 Tcl Max.
Figure 16. Application Circuit GND IGN BUS D1 C6 C5 C4 R2 C3 C1 R3 C2 R4 R1 28 27 26 25 24 23 22 1 21 2 20 3 19 MLP 7x7mm 0.
ATA6830 Table 5. Bill of Material Reference Component Value C1 Oscillator capacitor 100 pF, 5% C2 Bus input capacitor 1 nF C3 Ceramic capacitor 100 nF C4 Capacitor 10 µF C5 Capacitor 100 µF C6 Capacitor 100 nF D1 Rectifier – R1 Reference resistor 20 kW, 1% R2 Bus input resistor 1 kW, 5% R3 Shunt resistor side A 0.24 W, 5% R4 Shunt resistor side A 0.
Ordering Information Extended Type Number ATA6830-PKH Package HP-VFQFP-N28 Remarks 7 mm ´ 7 mm Package Information The package is a thermal power package MLF 7 ´ 7 with a soldered leadframe and 28 pins. The overall size is 7 ´ 7 mm2.
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