PBD3517-1

PBD3517-1 ERICSSON | Alldatasheet

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Technical content

Figure 1. Block diagram.

Description

PBD 3517/1 is a bipolar, monolithic, integrated circuit, intended to drive a stepper motor in a unipolar, bilevel way. One PBD 3517/1 and a minimum of external components form a complete control and drive unit for LS-TTL- or microprocessor-controlled stepper motor system for currents up to 500mA. The driver is suited for applications requiring least-posssible RFI. Motor performance can be increased by operating in a bilevel drive mode. This means that a high voltage pulse is applied to the motor winding at the beginning of a step, in order to give a rapid rise of current. Key Features

• Complete driver and phase logic on chip
• 2 x 350 mA continuous-output current
• Half- and full-step mode generation
• LS-TTL-compatible inputs
• Bilevel drive mode for high step rates
• Voltage-doubling drive possibilities
• Half-step position-indication output
• Minimal RFI
• 16-pin plastic DIP package or 16 pin small outline wide body PBD 3517/1 PBD 3517/1

Figure 2. Definition of symbols. Figure 3. Timing diagram.

1 PB2

2 PB1

5 PA2

4 PA1

3 GND

Electrical Characteristics

Electrical characteristics at TA = +25°C, VCC = +5.0 V, VMM = +40 V, VSS = +40 V unless otherwise specified. Ref. Parameter Symbol Fig. Conditions Min Typ Max Unit Supply current I CC 2 INH = LOW 45 60 mA

2 INH = HIGH 12 mA

Saturation voltage V PCE Sat 4I P = 350 mA 0.85 V Leakage current I PL 2V P = 0 V 500 µA Turn on, turn off t d 3 +70 °C3 µs td 3 +125 °C6 µs Second-level outputs Saturation voltage V LCE Sat 4I L = -350 mA 2.0 V Leakage current I LL 2V L = 0 V -500 µA On time t On 11 (note 4) 220 260 300 µs Logic inputs Voltage level, HIGH V IH 2 2.0 V Voltage level, LOW V IL 2 0.8 V Input current, low I IL 2V I = 0.4 V -400 µA Input current, high I IH 2V I = 2.4 V 20 µA Logic outputs Saturation voltage V ØCE Sat 5I Ø = 1.6 mA 0.4 V Notes 1. All voltages are with respect to ground. Current are positive into, negative out of specified terminal. 2 Derates at 12,8 mW/°C above +25°C. 3. Derates at 10.4 mW/°C above +25°C. 4. RT = 47 kΩ , CT = 10 nF. Figure 5. Typical second level saturation Figure 4. Typical phase output saturation

11 P B2 Phase output 2, phase B. Open collector output capable of sinking max 500 mA. 22 P B1 Phase output 1, phase B. Open collector output capable of sinking max 500 mA. 3 3 GND Ground and negative supply for both V CC and VSS . 44 P A1 Phase output 1, phase A. 55 P A2 Phase output 2, phase A. 6 6 DIR Direction input. Determines in which rotational direction steps will be taken. 7 7 STEP Stepping pulse. One step is generated for each negative edge of the step signal. 8 8 ØB Zero current half step position indication output for phase B. 9 9 ØA Zero current half step position indication output for phase A. mot. When pulled low, one step pulse will correspond to a half step of the motor. 11 11 INH A high level on the inhibit input turns all phase output off. 13 13 LA Second level (bilevel) output, phase A. 14 14 LB Second level (bilevel) output, Phase B. SS Second level supply voltage, +10 to +40 V. 16 16 V CC Logic supply voltage, nominally +5 V. Figure 13. Pin configuration.

data, the L/R time-constant. more-rapid rise of current, see figure 11. of STEP, see timing diagram, figure 3. correspond to a half step of the motor. Figure 15. Voltage

Purpose of external components For figures 14 and 15. Note that “Larger than …” is normally the vice versa of “Smaller than … .” Component Purpose Value Larger than value Smaller than value D1, D2 Passes low power to motor and prevents high power from shorting through low power supply If = 1A 1N4001, UF4001 Increases price Decreases max current capability D3 … D6 Inductive current supressor Increases price Decreases current turn-off capability trr = 100nS e.g. BYV27 UF4001 RGPP10G RGPP30D Slows down turn- off time. Voltage at anode might exceed voltage breakdown Speeds up turn- off time. R1 Base drive current limitter R = 20ohm Slows down Q1’s turn-on and Q4’s turn-off time. Speeds up Q1’s turn-on and Q4’s turn-off time. R2, R3 Base discharge resistor R = 240ohm Slows down Q1’s turn-off and Q4’s turn-on time. Speeds up Q1’s turn-off and Q4’s turn-on time. R4 … R7 External transistor base driver Vmm - Vbe - VceR = P > (I4)2 • R4 Check hfe. Decreases ext. transistor IC max. Lowers 3517 power dissipation. Increases ext. transistor IC max. Increases 3517 power dissipation. R8, R9 ØA, ØB pull-up resistors R = 5ohm @ pull-up voltage = 5V. Increases noise sensitivity, worse logic-level definition Increases noise immunity, better logic-level definition. Less stress on ØA, ØB output transistors Stress on ØA, ØB output transistors. R10, R11 Limit max. motor current. Resistors may be omitted. (Check motor specifications first.) Vmm -VMotor -VCESatR = IMotor max Decreases motor current. Increases motor current. R12 … R15 External transistor base discharge. Vbe R = ª 15WI12 P > Vbe • I12 Slows down external transistor turn-off time. Lowers 3517 power dissipation Speeds up external transistor turn-off time. Increases 3517 power dissipation RT, CT Sets L A and LB on time when triggered by STEP. R = 47kohm, C = 10nf P < 250mW Increases on time. Decreases on time. C1, C2 Stores the doubling voltage. C = 100µ F VC ‡ 45V Increases effective on-time during voltage doubling Decreases effective on-time during voltage doubling. C3 … C5 Filtering of supply- voltage ripple and take- up of energy feedback from D3 … D6 C µ F Increases price, better filtering, decreases risk of IC breakdown Decreases price, more compact solution. VRated >Vmm ,Vss or Vcc Increases price Risk for capacitor breakdown. Q1, Q2 Activation transistor of voltage doubling. IC as motor requires. Increases price. Decreases max Im during voltage doubling. Q3, Q4 Charging of voltage doubling capacitor Q5 … Q8 Motor current drive transistor. PNP power trans. Increases max current capability. Decreases max current capability. If = 1A VmmP = R1 )R1 + R2( VmmP = R1 )R1 + R2( VbeI4 - )R12( (VCC )2 P = R (Vmm - Vf -VCE ) • C1 IC = ( - 0.55 • RT • CT fStep ) IC as motor requires. 10‡ INH — Inhibit A HIGH level on the INH input,turns off all phase outputs to reduce current consumption. Reset An internal Power-On Reset circuit connected to V cc resets the phase logic and inhibits the outputs during power up, to prevent false stepping. Output Stages The output stage consists of four open- collector transistors. The second high- voltage supply contains Darlington transistors. Phase Outputs The phase outputs are connected directly to the motor as shown in figure 14. Bilevel Technique The bilevel pulse generator consists of two monostables with a common RC network. The internal phase logic generates a trigger pulse every time the phase changes state. The pulse triggers its own monostable which turns on the output transistors for a precise period of time: t On = 0.55 • CT • RT. See pulse diagrams, figures 16 through 20. Bipolar Phase Logic Output The ØA and ØB outputs are generated from the phase logic and inform an external device if the A phase or the B phase current is internally inhibited. These outputs are intended to support if it is legal to correctly go from a half-step mode to a full-step mode without loosing positional information. The PBD 3517/1 can act as a controller IC for 2 driver ICs, the PBL 3770A. Use P A1 and PB1 for phase control, and ØA and Ø B for I0 and I1 control of current turn-off. Applications Information Logic inputs If any of the logic inputs are left open, the circuit will treat it as a high-level input. Unused inputs should be connected to proper voltage levels in order to get the highest noise immunity. Phase outputs

Zener diode T O C (figure 23) Relatively high VZ gives: — Relatively fast current decay — Energy lost mainly in V Z — Potential cooling problems Power return T O C for unipolar drive (figure 24) Relatively high V Z gives: — Relatively fast current decay — Energy returned to power supply — Only small energy losses — Winding leakage flux must be considered — Potential cooling problems Power return to T O C for bilevel drive (figure 25) — Very fast current decay — Energy returned to power supply — Only small energy losses — Winding leakage flux must be considered Common Fault Conditions

• V MM supply not connected, or VMM supply not connected through diodes.
• The inhibit input not pulled low or floating. Inhibit is active high.
• A bipolar motor without a center tap is used. Exchange motor for unipolar version. Connect according to figure 14.
• External transistors connected without proper base-current supply resistor.
• Insufficient filtering capacitors used.
• Current restrictions exceeded. A and LB used for continuous output at high currents. Use the RC network to set a proper duty cycle according to specifications, see figures 6 through 11.
• A common ground wire is used for all three power supplies. If possible, use separate ground leads for each supply to minimize power interference. Ericsson Components AB SE-164 81 Kista-Stockholm, Sweden Telephone: +46 8 757 50 00 Specifications subject to change without notice. 1522-PBD 3517/1 Uen Rev. C © Ericsson Components AB 1999 Information given in this data sheet is believed to be accurate and reliable. However no responsibility is assumed for the consequences of its use nor for any infringement of patents or other rights of third parties which may result from its use. No license is granted by implication or otherwise under any patent or patent rights of Ericsson Components. These products are sold only according to Ericsson Components' general conditions of sale, unless otherwise confirmed in writing. Drive Circuits If high performance is to be achieved from a stepper motor, the phase must be energized rapidly when turned on and also de-energize rapidly when turned off. In other words, the phase current must increase/decrease rapidly at phase shift. Phase Turn-off Considerations When the winding current is turned off the induced high voltage spike will damage the drive circuits if not properly suppres- sed. Different turn-off circuits are used; e. g. : Diode turn-off circuit (figure 21) — Slow current decay — Energy lost mainly in winding resistance — Potential cooling problems. Resistance T O C (figure 22) — Somewhat faster current decay — Energy lost mainly in R-Ext — Potential cooling problems

Ordering Information

Package Part No. DIP Tube PBD 3517/1NS SO Tube PBD 3517/1SOS SO Tape & Reel PBD 3517/1SOT