Datasheet LB1845 Datasheet (SANYO)

Page 1

Overview

The LB1845 is a PWM current control type stepping motor driver that uses a bipolar drive scheme. It is particularly suitable for driving carriage and paper feed stepping motors in printers and similar products.

Features

• PWM current control (fixed off time scheme)

• Digital load current selection function

• Sustained output voltage: 45 V

• Built-in thermal shutdown circuit

Package Dimensions

unit: mm

3147A-DIP28H

Monolithic Digital IC

Ordering number: EN5505B

D3096HA (OT) No. 5505-1/7

SANYO: DIP28H

[LB1845]

SANYO Electric Co.,Ltd. Semiconductor Bussiness Headquarters

TOKYO OFFICE Tokyo Bldg., 1-10, 1 Chome, Ueno, Taito-ku, TOKYO, 110 JAPAN

PWM Current Control Stepping Motor Driver

LB1845

Parameter Symbol Conditions Ratings Unit

Motor supply voltage V

45 V

Peak output current I

OPEAKtW

= 20 µS 1.75 A

Continuous output current I

OMAX

1.5 A

Logic block supply voltage V

7.0 V

Logic input voltage range V

–0.3 to V

Emitter output voltage V

1.0 V

Allowable power dissipation

Pd max1 Independent IC 3.0 W

Pd max2 With an arbitrarily large heat sink 20.0 W Operating temperature Topr –20 to +85 °C Storage temperature Tstg –55 to +150 °C

Specifications

Absolute Maximum Ratings at Ta = 25°C

Parameter Symbol Conditions Ratings Unit

Motor supply voltage V

10 to 44.5 V

Logic block supply voltage V

4.75 to 5.25 V

Reference voltage V

REF

1.5 to 7.5 V

Recommended Operating Ranges at Ta = 25°C

Page 2

No. 5505-2/7

LB1845

Parameter Symbol Conditions

Ratings

Unit

min typ max

[Output Block]

Output stage supply voltage

BB ON

12 16 mA

BB OFF

0.7 0.9 mA

(sat)1 IO= +1.0 A sink 1.2 1.4 V

Output saturation voltage 1

(sat)2 IO= +1.5 A sink 1.4 1.7 V

(sat)3 IO= –1.0 A source 1.1 1.3 V

(sat)4 IO= –1.5 A source 1.3 1.6 V

Output leakage current

(leak)1 VO= VBBsink 50 µA

(leak)2 VO= 0 V source –50 µA

Sustained output voltage V(sus) * 45 V

[Logic Block]

Logic supply current

CC ON

I0 = 0.8 V, I1 = 0.8 V 19.5 25.3 mA

CC OFF

I0 = 2.4 V, I1 = 2.4 V 15.5 20.1 mA

Input voltage

2.4 V

0.8 V

Input current

VIH= 2.4 V 10 µA

VIL= 0.8 V –10 µA I0 = 0.8 V, I1 = 0.8 V 9.5 10 10.5

Current control threshold voltage V

REF/VSENSE

I0 = 2.4 V, I1 = 0.8 V 13.5 15 16.5 I0 = 0.8 V, I1 = 2.4 V 25.5 30 34.5

Thermal shutdown temperature T

170 °C

Electrical Characteristics at Ta = 25°C, VBB= 38 V, VCC= 5 V, V

REF

= 5 V

Truth Table

Pin Assignment

Note: *Design guaranteed value

Note: Outputs go off when ENABLE is high or in the I0 = I1 = high state.

ENABLE PHASE OUT A OUT B

L H H L L L L H H — OFF OFF

I0 I1 Output current

L L V

REF

/ (10 × RE) = I

OUT

H L V

REF

/ (15 × RE) = I

OUT

× 2/3

L H V

REF

/ (30 × RE) = I

OUT

× 1/3

H H 0

Page 3

Block Diagram

Application Circuit Diagram

No. 5505-3/7

LB1845

Page 4

Pin Functions

Timing chart for pin switching operations during PWM drive

Figure 1 Switching Waveforms

toff: Output off time. Determined by external capacitor and resistor Ct and Rt. (toff = Ct × Rt) td: Delay time between the point the set current is sensed at the SENSE pin and the point the output turns off.

No. 5505-4/7

LB1845

Pin no. Pin Function

1, 14 V

Output stage power-supply voltage

2 SENSE1 Set current detection pins.

13 SENSE2 Connect these pins, fed back through noise filters, to E1 and E2.

3 E1 The set current is controlled by the resistors Re inserted between these pins and ground.

12 E2

4, 11 D-GND Internal diode anode connection

6 OUT 1B Outputs 7 OUT 1A 8 OUT 2B

9 OUT 2A 15 GND Ground 27 RC1 Used to set the output off time for the switched output signal. 16 RC2 The fixed off times are set by the capacitors and resistors connected to these pins. toff = CR. 26 V

REF

1 Output current settings

17 V

REF

2 The output current is determined by the voltage (in the range 1.5 to 7.5 V) input to these pins. 25 PHASE1 Output phase switching inputs. 18 PHASE2 High-level input: OUT A = high, OUT B = low

Low-level input: OUT A = low, OUT B = high 24 ENABLE1 Output on/off settings 19 ENABLE2 High-level input: output off

Low-level input: output on

22, 23 I01, I11 Digital inputs that set the output current 21, 20 I02, I12 The output currents can be set to 1/3, 2/3, or full by setting these pins to appropriate combinations of high and low levels.

28 V

Logic block power supply

Page 5

Usage Notes

1.External diode Since this IC adopts a system based on lower side transistor switching drive, an external diode for the regenerative current that occurs during switching is required between VBBand V

OUT

. Use a Schottky barrier diode with a low

feedthrough current.

2.Noise filters Since spike noise (see Figure 1) occurs when switching to the on state due to the external diode’s feedthrough current, applications must remove noise from the SENSE pin with a noise filter (Cc, Rc) between the E pin and the SENSE pin. However, note that if the values of Cc and Rc are too large, the SENSE voltage rise will be slowed, and the current setting will be shifted towards a higher current level.

3.V

REF

It is possible to change the output current continuously by continuously changing the V

REF

pin voltage. However, this

voltage cannot be set to 0 V. The V

REF

pin input impedance is 26 kΩ (±30%) when V

REF

is 5 V. Since this pin is used

to set the output current, applications must be designed so that noise does not appear on this pin's input.

4.GND pin Since this IC switches large currents, care must be taken to avoid ground loops when the IC is mounted in the application. The section of the PCB that handles large currents should be designed with a low-impedance pattern, and must be separated from the small signal sections of the circuit. In particular, the ground for the sense resistor Re must be as close as possible to the IC ground.

5.Operation in hold mode There are cases where a current somewhat larger than the current setting may flow in hold mode (light load mode). Since this IC adopts a lower side switching, lower side sense system, the emitter voltage falls and the sense voltage goes to 0 when the switching state goes to off. The circuit then always turns the output on after the toff period has elapsed. At this time, due to the light load, the existence of the time td, and the fact that the output goes on even if the output current is higher than the set current, the output current will be somewhat higher than the set current. Applications should set the current setting somewhat lower than required if this occurs.

6.Function for preventing the upper and lower outputs being on at the same time This IC incorporates a built-in circuit that prevents the through currents that occur when the phase is switched. The table lists the output on and off delay times when PHASE and EANBLE are switched.

7.1-2 phase excitation and the double 1-2 phase excitation control sequence To reduce the vibration that occurs when the motor turns, this IC supports 1-2 phase excitation and double 1-2 phase excitation by using the output current setting digital input pins I0 and I1 without changing the V

REF

pin voltage. Tables 1 and 2 list that control sequence, and Figure 2 and Figure 3 present the composite vector diagram for this sequence.2. Noise filters

No. 5505-5/7

LB1845

Sink side Source side

When PHASE is switched

On delay time 10 µs 9 µs Off delay time 1.5 µs 3 µs

When ENABLE is on

On delay time 9 µs 9 µs Off delay time 1.5 µs 6.5 µs

No.

Phase A Phase B

PH1 I11 I01 Current value PH2 I12 I02 Current value 0 0 0 0 1 * 1 1 0 1 0 0 1 2/3 0 0 1 2/3 2 * 1 1 0 0 0 0 1 3 1 0 1 2/3 0 0 1 2/3 4 1 0 0 1 * 1 1 0 5 1 0 1 2/3 1 0 1 2/3 6 * 1 1 0 1 0 0 1 7 0 0 1 2/3 1 0 1 2/3

Table 1 [1-2 phase excitation] 1/2 step

ENABLE1 = ENABLE2 = 0

Page 6

No. 5505-6/7

LB1845

No.

Phase A Phase B

PH1 I11 I01 Current value PH2 I12 I02 Current value 0 0 0 0 1 * 1 1 0 1 0 0 0 1 0 1 0 1/3 2 0 0 1 2/3 0 0 1 2/3 3 0 1 0 1/3 0 0 0 1 4 * 1 1 0 0 0 0 1 5 1 1 0 1/3 0 0 0 1 6 1 0 1 2/3 0 0 1 2/3 7 1 0 0 1 0 1 0 1/3 8 1 0 0 1 * 1 1 0 9 1 0 0 1 1 1 0 1/3

10 1 0 1 2/3 1 0 1 2/3 11 1 1 0 1/3 1 0 0 1 12 * 1 1 0 1 0 0 1 13 0 1 0 1/3 1 0 0 1 14 0 0 1 2/3 1 0 1 2/3 15 0 0 0 1 1 1 0 1/3

Table 2 [Double 1-2 phase excitation] about 1/4 step

Composite Vector Diagram

Figure 2 Composite Vector Diagram for the

Sequence in Table 1 (1/4 cycle)

Figure 3 Composite Vector Diagram for the

Sequence in Table 2 (1/4 cycle)

ENABLE1 = ENABLE2 = 0

Page 7

No. 5505-7/7

LB1845

This catalog provides information as of December, 1996. Specifications and information herein are subject to change without notice.

■ No products described or contained herein are intended for use in surgical implants, life-support systems, aerospace equipment, nuclear power control systems, vehicles, disaster/crime-prevention equipment and the like, the failure of which may directly or indirectly cause injury, death or property loss.

■ Anyone purchasing any products described or contained herein for an above-mentioned use shall:

➀

Accept full responsibility and indemnify and defend SANYO ELECTRIC CO., LTD., its affiliates, subsidiaries and distributors and all their officers and employees, jointly and severally, against any and all claims and litigation and all damages, cost and expenses associated with such use:

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Not impose any responsibility for any fault or negligence which may be cited in any such claim or litigation on SANYO ELECTRIC CO., LTD., its affiliates, subsidiaries and distributors or any of their officers and employees jointly or severally.

■ Information (including circuit diagrams and circuit parameters) herein is for example only; it is not guaranteed for volume production. SANYO believes information herein is accurate and reliable, but no guarantees are made or implied regarding its use or any infringements of intellectual property rights or other rights of third parties.