PG001M ALLEGRO
Document overview
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Technical content
The PG001M CMOS IC converts parallel-data signals from a low- cost, 8-bit microprocessor or microcontroller into a serial-data format compatible with the SLA7042M and SLA7044M power multi-chip modules to drive unipolar PWM, high-current stepper motors. The converter provides for five basic modes of operation: 1) normal, two-phase, full step (100% torque vector), 2) two-phase 'boosted' torque (141% torque vector), 3) half-step, constant torque operation (using a 2-1-2 output switching), 4) quarter-stepping utilizing ratioed currents for constant torque, and 5) microstepping (1/8th steps) for quiet, smooth, resonance-free motor performance. The PG001M is supplied in a low-cost 16-pin dual in-line plastic package. It is rated for continuous operation over the temperature range of -20°C to +85°C. Always order by complete part number, PG001M .
FEATURES
I Intended For Use With SLA7042M or SLA7044M Microstepping, Unipolar PWM, High-Current Motor Drivers I Supports Five Stepper-Motor Operating Modes I µP-Compatible Inputs Data Sheet 26112 PG001M MODE SELECT. .2 MODE SELECT. .1 Dwg. PK-009 MONITOR VECTOR CONTROL CCW/CW RESET STROBE NO CONNECT. GROUND CONTROL SUPPLY NOT USABLE CONTROL LOGIC PARALLEL-TO-SERIAL CONVERTER NOT USABLE CLOCKIN CLOCK SERIAL DATA OUT A B SERIAL DATA V DD Input Voltage Range, Output Voltage Range, Operating Temperature Range, Storage Temperature Range, CAUTION: CMOS devices have input static protection but are susceptible to damage if exposed to extremely high static electrical charges. ABSOLUTE MAXIMUM RATINGS PARALLEL-TO-SERIAL DATA CONVERTER
115 Northeast Cutoff, Box 15036
Worcester, Massachusetts 01615-0036 (508) 853-5000 Copyright © 1998, Allegro MicroSystems, Inc. FUNCTIONAL BLOCK DIAGRAM SERIAL DATAA SERIAL DATAB CLOCK OUT STROBE Dwg. FK-009A MODE SELECT2 MODE SELECTOR OSC. PARALLEL-TO-SERIAL CONVERTER UP-DOWN COUNTER SEQUENCING LOGIC MODE SELECT CLOCK CCW/CW RESET a b c PHASE SET IN VECTOR CONTROL MONITOR
12 NO (INTERNAL)
SLA7042/44M Output Sequence & PWM Current Motor Inputs Motor Excitation VC MS1 MS2 20% 40% 55.5% 71.4% 83% 91% 100% Torque Full Step H L L I 141% L L L I 100% Half Step X H L I I I 100% 1/4 Step X L H I I I I I 100% 1/8 Step X H H I I I I I I I I 100%
ELECTRICAL CHARACTERISTICS at TA = +25°C, VDD = 5 V (unless otherwise noted). Limits Characteristic Symbol Test Conditions Min. Typ. Max. Units Supply Voltage VDD Operating 4.5 5.5 V Output Voltage VOH IO = -3 mA 4.5 4.6 V VOL IO = 3 mA 0.3 0.4 V Input Current IIH VI = 5 V 1.0 µA IIL VI = 0 V -1.0 µA Input Voltage VIH 3.5 5.0 V VIL 1.5 V Vhys 1.0 V Internal Oscillator Freq. fosc 1.5 MHz Delay Time td(CIH-COH) CLKIN to CLKOUT rising edges 100 ns td(CIL-SL) CLKIN to STROBE falling edges 430 550 ns Output Switching Time tr CL = 15 pF, 10% to 90% ns tf CL = 15 pF, 90% to 10% ns CLOCKIN Pulse Width tckH 4.5 µs tckL 0.5 µs Input Capacitance ci 5.0 pF Supply Current IDD VDD = 5.5 V 350 450 µA CLOCKIN RESET MODE SELECT CCW/CW VECTOR CONTROL ≥100 ns Dwg. WK-005 ≥100 ns ≥100 ns ≥0.5 µs ≥4.5 µs PG001M Input Signals Timing
Worcester, Massachusetts 01615-0036 (508) 853-5000 CLOCK, STROBE, and SERIAL DATA Outputs for Microstepping CLOCKOUT STROBE LSB MSB PHASE 1/8 STEP 100% 1/4 STEP 91% 3/8 STEP 83% 1/2 STEP 71.4% 5/8 STEP 55.5% 3/4 STEP 40% 7/8 STEP 20% FULL STEP X X X X X X X X 20% 40% 55.5% 71.4% 83% 91% 100% 100% FULL STEP 100% X FULL STEP (141% TORQUE) 100% Dwg. WK-007 100% X SERIAL DATA A SERIAL DATA B X X X X X X X X X X
PG001M DESCRIPTION AND OPERATION The PG001M is a CMOS step-motor control IC that converts parallel-input signals from a microprocessor (µP, or microcontroller, µC) to the serial-input data format required for control of an SLA7042M or SLA7044M microstepping, unipolar PWM, high-current motor driver. This control IC offers five basic modes of motor operation: normal 2-phase, full-step (100% torque vector); 2-phase, full-step 'boosted' torque (141% vector); 1/2-step, constant torque operation (i.e., 2-1-2 switching); 1/4-step operation with current-ratioed constant torque; and smooth microstepping operation (1/8th step) for resonance-free motor performance (constant torque with eight output current ratios). Three inputs (VC, MS1, and MS2) control these five operational modes (as shown in figure 1); this enables designers to change the drive method during movement to realize optimal performance. Initially, at start-up, the high-torque mode can provide 141% torque (the resulting vector of both motor windings at 100% current). This enhances rapid acceleration (and deceleration). Switching to quarter-stepping or microstepping (after initial, startup acceleration) offers smooth, resonance-free operation during the ramp-up interval. The transition to quarter- or microstepping should occur before the increasing step rate approaches the motor resonance frequency (usually 100 to 200 Hz). The modes of operation and current-control truth table are listed on page 2; and there are two full-step, 2-phase (2-2) operating modes. The VECTOR CONTROL input (VC) can only be changed when MONITOR (MO, a readback pin) is LOW and the PG001M is operating in the full-step mode. Starting (or stopping) the step motor with VC HIGH delivers the highest torque (141%) from the motor, and is the extension of two outputs ON at 71.4%. This 'half-step' rotor position corresponds to the state when MO is LOW, and switching the control inputs to another operating mode is allowed. The PG001M accepts logic signals from the µP and converts these into the proper serial-data format required to control the serial-data input lines of the SLA7042M or SLA7044M microstepping power modules. The five control inputs determine the various modes of operation. The CLOCKOUT, SERIAL DATAA, SERIAL DATAB, and STROBE to the SLA7042/44M are synchronized to the CLOCKIN of the PG001M; and the CLOCKIN frequency is eight times the step rate (more to follow on the signal/ timing relationships). The internal logic and oscillator combine to convert the parallel input signals to 'bursts' of serial data from the A A B B AB AB AB AB ONE-PHASE, FULL-STEP MODE (WITHOUT PG001M) TWO-PHASE, FULL-STEP MODE (MS1 = L, MS2 = L, VC = L) 1/4-STEP MODE (MS1 = L, MS2 = H, VC = X) 1/8-STEP MODE (MS1 = H, MS2 = H, VC = X) Dwg. OP-005 TWO-PHASE, FULL-STEP MODE MAXIMUM TORQUE (141%) (MS1 = L, MS2 = L, VC = H) 1/2-STEP MODE CONSTANT TORQUE (MS1 = H, MS2 = L, VC = X) AB AB AB AB A A B B AB AB AB AB A A B B AB AB AB AB A A B B AB AB AB AB NOTE – Mode change only allowed at half-step positions (refer to upper right figure). Figure 1 — Current/Displacement Vectors
eight distinct, exact positions is often very challenging. accurate, intermediate step divisions. figure 2. In addition to the 45° AB vector, three other half- four 2-phase, full steps of rotation. operation produces 'bursts' at 1/4 the input clock rate. decreases as the step motor and load are decelerating. SLA7042M or SLA7044M power multi-chip modules.
Figure 3 — Typical 'Integrated' Microstepping System REF/ENABLE CLOCK STROBE SERIAL DATA SERIAL DATA Dwg. EK-014A MODE SELECT MONITOR CCW/CW RESET VECTOR CONTROL MODE SELECT2 µP CLOCK IN SLA7042M or SLA7044M RS B RS A GND B GND A PG001M GND A A B B VDD A A B A B A B OUT VBB CONTROL SUPPLY B +5 V A B After the RESET pulse, the first (two) full-steps in the microstepping sequence, MS1 is switched LOW and the control IC shifts into the 1/4-step mode. It becomes very apparent that any microstepping directly from a µP to the SLA7042/44M module 'burdens' the µP, complicates the software, and might entail a 'dedicated' microcontroller in many motion-control systems. The PG001M controller IC precludes loading a µP with direct serial-data signals to the power multi-chip module. Because the step motor is updated at eight times the step rate, this CMOS IC both simplifies software and eliminates loading a system microprocessor with 'house- keeping' control of step motors. As illustrated in figures 4 and 5, the controller IC eliminates the requirement to program the system for the various modes of operation and the continual updating of the serial-data signals to the power multi-chip module. NOTE — In figures 4 and 5, the clock frequency is constant during the few steps of operation that are shown and half-step operation is not included. Depicted in figure 4 are the 'front-end' I/O signals (from RESET to VECTOR CONTROL), converted signals from the controller IC to the microstepping power module (CLOCKOUT, SERIAL DATAA, SERIAL DATAB, and STROBE), plus the MONITOR (readback) to the microcontroller. Finally, the power multi-chip module current ratios are illustrated (OUTA and OUTB). As shown, initially the counter is reset, and then the motor is operating in quarter-step mode; then MS2 is switched while MO is LOW. The two steps following are full-step (100% torque vector). The final (fourth quadrant) portion of figure 4 is the maximum (141%) torque mode, after VECTOR CONTROL has been switched from LOW to HIGH. Three of the five operational modes are shown, and none require the µP to continually update the clock, serial-data input, or strobe to the SLA7042/44M module. The microstepping operation is illustrated in figure 5. Initially the counter is reset, and with both MODE SE- LECTs HIGH the controller is furnishing clock, serial data, and strobe logic signals for 1/8th step increments.
Worcester, Massachusetts 01615-0036 (508) 853-5000 Because the parallel-to-serial conversion requires six 'static' logic signals plus a 'dynamic' (clock) input, the addition of latches between the µP and five of the control- ler IC inputs permits use on a bus. Latching the five signals to CCW/CW, MS1, MS2 , RESET, and VC frees these five I/O lines for other operations by the microcontroller. Even at extremely high step rates (>5 kHz), updating the PG001M input data requires an infini- tesimal percentage of the µP's I/O and control operations. Figure 4 — Quarter-Step, Full-Step, and High-Torque Full-Step RESET CLOCK IN CCW/CW MODE SELECT MODE SELECT VECTOR CONTROL CLOCK OUT SERIAL DATA A SERIAL DATAB STROBE MONITOR 71.4 71.4 71.4 71.4 100 71.4 100 71.4 71.4 71.4 100 Dwg. WK-006 1/4-STEP MODE FULL-STEP MODE PER CENT OUTA B PER CENT OUT 71.4 -40 -71.4 71.4 -71.4 -71.4 THIRD QUADRANT FOURTH QUADRANT FIRST QUADRANT SECOND QUADRANT FIRST QUADRANT -71.4 71.4 100 71.4 100 100 FULL-STEP MODE MAXIMUM TORQUE (141%)
The clock input frequency limit is derived from the figure on page 3. The minimum period for the clock pulse HIGH is 4.5 µs, plus a minimum LOW interval of 0.5 µs; this limits the upper clock frequency to ≤200 kHz. Updat- ing the operating mode of the controller IC requires only one clock period (≥5 µs), and the five I/O lines on the bus remain unchanged until a signal is required to change the operating mode, reverse direction, vary torque, etc. One technique to free µP I/O lines for shared functions is depicted in figure 6. The I/O lines required (without latches) are then transformed into three 'dedicated' logic inputs; a STROBE is added, and CLOCK and MONITOR retained. CLOCK, RESET, MODE SELECT1, MODE SELECT2, and VECTOR CONTROL now connect to a bus. Figure 5 — Microstepping (1/8th-Step) and Quarter-Step Modes RESET CLOCK IN CCW/CW MODE SELECT MODE SELECT VECTOR CONTROL CLOCK OUT SERIAL DATA A SERIAL DATAB STROBE MONITOR 71.4 55.5 55.5 71.4 100 100 100 71.4 71.4 100 71.4 71.4 100 100 100 71.4 55.5 55.5 71.4 100 71.4 71.4 71.4 55.5 -20 -40 -55.5 -71.4 -83 -91 -100 -100 -100 -91 -83 -71.4 -40 71.4 100 71.4 71.4 100 100 100 71.4 55.5 -20 -40 -55.5 -71.4 -91 -100 -91 -71.4 -40 71.4 Dwg. WK-006-1 1/8-STEP MODE 1/4-STEP MODE PER CENT OUTA B FIRST QUADRANT SECOND QUADRANT THIRD QUADRANT FOURTH QUADRANT FIRST QUADRANT PER CENT OUT
Worcester, Massachusetts 01615-0036 (508) 853-5000 Figure 6 — A Latched Input-Bus Configuration CLOCK STROBE SERIAL DATA SERIAL DATA Dwg. EK-014-1 MODE SELECT CCW/CW RESET VECTOR CONTROL MODE SELECT2 MONITOR CLOCK IN µP PG001M GND VDD +5 V LATCHES (5) GND VCC STROBE VCC A B At start-up, reseting the counter adds only another clock interval (per figures 4 and 5). During high-speed slewing, the µP is only occupied with sending clock signals and monitoring the readback (MO). Hence, of a 200 µs interval, with a slewing rate of 5 kHz, only 5 µs is required to provide the clock input. At slower, more typical step rates, 5 µs becomes an insignificant burden on the µP controlling the stepping motor. Other techniques to decrease and unburden the essen- tial µP I/O lines and control logic are viable. Utilizing an 8-bit shift register (serial-to-parallel conversion) between the µP and the controller IC further reduces the I/O lines, and HCMOS logic provides serial-data entry at 20 MHz (vs <200 kHz). Such a design could further decrease the interval required to update the step-motor operation and reduce the I/O lines on the bus.
(controlling dimensions) Dimensions in Millimeters (for reference only) 0.355 0.204 7.62 BSC Dwg. MA-001-16A mm 10.92 MAX 7.11 6.10 5.33 MAX 1.77 1.15 0.39 MIN 0.558 0.356 2.54 BSC 0.13 MIN 3.81 2.93 19.68 18.67 0.014 0.008 0.300 BSC Dwg. MA-001-16A in 0.430 MAX 0.280 0.240 0.210 MAX 0.070 0.045 0.015 MIN 0.022 0.014 0.100 BSC 0.005 MIN 0.150 0.115 0.775 0.735 NOTES:1. Lead thickness is measured at seating plane or below. 2. Lead spacing tolerance is non-cumulative. 3. Exact body and lead configuration at vendor’s option within limits shown.
Worcester, Massachusetts 01615-0036 (508) 853-5000 The products described here are manufactured in Japan by Sanken Electric Co., Ltd. for sale by Allegro MicroSystems, Inc. Sanken Electric Co., Ltd. and Allegro MicroSystems, Inc. reserve the right to make, from time to time, such departures from the detail specifications as may be required to permit improvements in the design of their products. The information included herein is believed to be accurate and reliable. However, Sanken Electric Co., Ltd. and Allegro MicroSystems, Inc. assume no responsibility for its use; nor for any infringements of patents or other rights of third parties which may result from its use.