PBL3771-1 ERICSSON | Alldatasheet

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Technical content

Description

The PBL 3771/1 is a switch-mode, constant-current driver IC (chopper) with two channels, one for each winding of a two-phase stepper motor. The circuit is especially developed for use in microstepping applications in conjunction with the matching dual DAC (Digital-to-Analog Converter) PBM 3960. A complete driver system consists of these two ICs, a few passive components and a microprocessor for generation of the proper control and data codes required for microstepping. The PBL 3771/1 contains a clock oscillator, which is common for both driver channels; a set of comparators and flip-flops implementing the switching control; and two H-bridges with internal recirculation diodes. Voltage supply requirements are +5 V for logic and +10 to +45 V for the motor. Maximum output current is 650 mA per channel. A special logic function is used to select slow or fast current decay in the output stage for improved high-speed microstepping. The close match between the two driver channels guarantees consistent output current ratios and motor positioning accuracy. PBL 3771/1 Precision Stepper Motor Driver Figure 1. Block diagram.

  • Dual chopper driver in a single package.
  • 650 mA output current per channel.
  • Close matching between channels for high microstepping accuracy.
  • Selectable slow/fast current decay for improved high-speed microstepping.
  • Improved low-level linearity.
  • Specially matched to Dual DAC PBM 3960.
  • Selection of packages, 22-pin “batwing” DIP, 24 pin "batwing" SOIC or 28-lead PLCC with lead-frame for heat-sinking through PC board copper. RC PBL 3771/1 V MM1 V MM2 M A1 M B1 M B2 M A2 GNDC 2V R2CD 2Phase 2 VCC C 1V R1CD 1Phase 1 E 1 E 2 VCC S R Q Logic S R Q Logic PBL 3771/1 PBL 3771/1 PBL3771/1

****See operating temperature chapter. Figure 2. Definitions of symbols. Figure 3. Definition of terms.

Electrical Characteristics

Electrical characteristics over recommended operating conditions, unless otherwise noted. -20°C - TJ - +125°C. Ref. Parameter Symbol fig. Conditions Min Typ Max Unit General Supply current I CC 38 50 mA Total power dissipation P D VMM = 40 V, IM1 = 450 mA, IM2 = 0 mA. 1.4 1.6 W Notes 2, 3. V MM = 40 V, IM1 = IM2 = 318 mA. 1.6 1.8 W Notes 2, 3. Turn-off delay t d 3T a = +25°C, dVC /dt ≥ 50 mV/µs. 1.0 1.5 µs Note 3. Logic Inputs Logic HIGH input voltage V IH 2.0 V Logic LOW input voltage V IL 0.8 V Logic HIGH input current I IH VI = 2.4 V 20 µA Logic LOW input current I IL VI = 0.4 V -0.4 mA Reference Inputs Input resistance R R Ta = +25°C 5 kohms Input current I R Ta = +25°C, VR = 2.5 V. 0.5 1.0 mA Turn-off voltage V TO 20 29 38 mV Comparator Inputs Threshold voltage V CH R C = 1 kohms, VR = 2.5 V 430 450 470 mV | VCH1 - VCH2 | mismatch V CH,diff R C = 1 kohms 1 mV Input current I C -10 1 µA Motor Outputs Lower transistor saturation voltage IM = 500 mA 1.00 1.20 V Lower transistor leakage current V MM = 41 V, VE = VR = 0 V, VC = VCC 300 µA Lower diode forward voltage drop I M = 500 mA 1.10 1.25 V Upper transistor saturation voltage IM = 500 mA 1.20 1.35 V Upper transistor leakage current V MM = 41 V, VE = VR = 0 V, VC = VCC 300 µA Upper diode forward voltage drop I M = 500 mA 1.00 1.25 V Chopper Oscillator Chopping frequency f s 3C T = 3300 pF, RT = 15 kohms 25.0 26.5 28.0 kHz Thermal Characteristics Ref. Parameter Symbol fig. Conditions Min Typ Max Unit Thermal resistance Rth J-BW 13 DIL package. 11 °C/W RthJ-A 13 DIL package. Note 2. 40 °C/W RthJ-BW 13 PLCC package. 9 °C/W RthJ-A 13 PLCC package. Note 2. 35 °C/W RthJ-BW 13 SO package. 13 °C/W RthJ-A 13 SO package. Note 2. 42 °C/W Notes 1. All voltages are with respect to ground. Currents are positive into, negative out of specified terminal. 2. All ground pins soldered onto a 20 cm2 PCB copper area with free air convection. 3. Not covered by final test program. 4. Switching duty cycle D = 30%, f S = 26.5 kHz.

1 E 2

1 C 2

Figure 4. Pin configuration. 21 8 M B1 Motor output B, channel 1. Motor current flows from MA1 to MB1 when Phase1 is HIGH. 32 1 0 E 1 Common emitter, channel 1. This pin connects to a sensing resistor to ground. 43 1 1 V MM1 Motor supply voltage, channel 1, 10 to 40 V. VMM1 and VMM2 should be connected together. 54 1 2 M A1 Motor output A, channel 1. Motor current flows from MA1 to MB1 when Phase1 is HIGH. 6,7, 5,6, 1-3,9, GND Ground and negative supply. Note: these pins are used thermally for heat-sinking. plane for efficient heat sinking. the output current. Input resistance is typically 2.5 kohms, ±20%. 12 11 22 V CC Logic voltage supply, nominally +5 V. ground to obtain the nominal switching frequency of 26.5 kHz. the output current. Input resistance is typically 2.5 kohms, ±20%. 20 19 4 M A2 Motor output A, channel 2. Motor current flows from MA2 to MB2 when Phase2 is HIGH. 21 20 5 V MM2 Motor supply voltage, channel 2, 10 to 40 V. VMM1 and VMM2 should be connected together. 22 21 6 E 2 Common emitter, channel 2. This pin connects to a sensing resistor to ground. 23 22 7 M B2 Motor output B, channel 2. Motor current flows from MA2 to MB2 when Phase2 is HIGH.

switching due to switching transients. set by the R-C combination at pin RC. Figure 7. Microstepping system with PBM 3960 /1 and PBL 3771/1. selected for maximum motor current. “Recommended Operating Conditions”). also be used, see figure 14.