L6506D013TR中文资料

L6506L6506D

July 2003CURRENT CONTROLLER FOR STEPPING MOTORS

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DESCRIPTION

The L6506/D is a linear integrated circuit designed to sense and control the current in stepping motors and similar devices. When used in conjunction with the L293, L298, L7150, L6114/L6115, the chip set forms a constant current drive for an inductive load and performs all the interface function from the con-trol logic thru the power stage.

Two or more devices may be synchronized using the sync pin. In this mode of operation the oscillator in the master chip sets the operating frequency in all chips.

DIP18 SO20ORDERING NUMBERS:

L6506 L6506D

BLOCK DIAGRAM (pin’s number referred to DIP-18)

1/8

PIN CONNECTIONS (top view)

ABSOLUTE MAXIMUM RATINGS

Symbol Parameter Value Unit V CC Supply Voltage10V V i Input Signals7V

P tot Total Power Dissipation (T amb = 70°C) for DIP18 Total Power Dissipation (Tamb = 70éC) for SO20

1

0.8

W

W

T j Junction Temperature150°C T stg Storage Temperature-40 to 150°C

THERMAL DATA

Symbol Parameter DIP18SO20Unit R th j-amb Thermal Resistance Junction-ambient Max.80100°C/W

ELECTRICAL CHARACTERESTICS (V CC = 5.0V, T amb = 25°C; unless otherwise noted)

Symbol Parameter Test Conditions Min.Typ.Max.Unit V CC Supply Voltage 4.57V

I CC Quiescent Supply Current V CC = 7V25mA

DIP18 SO20

COMPARATOR SECTION

Symbol Parameter Test Conditions Min.Typ.Max.Unit V IN Input Voltage Range V sense Inputs–0.33V V IO Input Offset Voltage V IN = 1.4V±5.0mV

I IO Input Offset Current±200nA

I IB Input Bias Current1μA

Response time V REF = 1.4V V SENS = 0 to 5V0.8 1.5μ

s

ELECTRICAL CHARACTERISTICS (continued)

COMPARATOR SECTION PERFORMANCE (Over Operating Temperature Range)

Symbol Parameter

Test Condtions

Min.

Typ.

Max.Unit V IO Input Offset Voltage V IN = 1.4V

±20mV I IO

Input Offset Curent

±500

nA

CIRCUIT OPERATION

The L6506 is intended for use with dual bridge driv-ers, such as the L298, quad darlington arrays, such as the L7150, quad DMOS array such as L6114-L6115, or discrete power transistors to drive stepper motors and other similar loads. The main function of the device is to sense and control the current in each of the load windings.

A common on-chip oscillator drives the dual chopper and sets the operating frequency for the pulse width modulated drive. The RC network on pin 1 sets the operating frequency which is given by the equation :

1

f =for R > 10 K

0.69 RC

The oscillator provides pulses to set the two flip-flops which in turn cause the outputs to activate the drive. When the current in the load winding reaches the programmed peak value, the voltage across the sense resistor (R sense ) is equal to V ref and the cor-responding comparator resets its flip-flop interrupt-ing the drive current until the next oscillator pulse oc-curs. The peak current in each winding is pro-grammed by selecting the value of the sense resis-

tor and V ref . Since separate inputs are provided for each chopper, each of the loads may be pro-grammed independently allowing the device to be used to implement microstepping of the motor.Lower threshold of L6506’s oscillator is 1/3 V CC . Up-per threshold is 2/3 V CC and internal discharge re-sistor is 1 K ? ± 30 %.

Ground noise problems in multiple configurations can be avoided by synchronizing the oscillators.This may be done by connecting the sync pins of each of the devices with the oscillator output of the master device and connecting the R/C pin of the un-used oscillators to ground.

The equations for the active time of the sync pulse (T2), the inactive time of the sync signal (T1) and the duty cycle can be found by looking at the figure 1 and are :

R1 R IN

T2 = 0.69 C1(1)

R1 + R IN

T1 = 0.69 R1 C1(2)T2DC =

(3)

T1 + T2

LOGIC SECTION (Over Operating Temperature Range - TTL compatible inputs & outputs)

Symbol Parameter

Test Condtions

Min.Typ.

Max.Unit V IH Input High Voltage 2

V s V V IL Input Low Voltage 0.8

V V OH Output High Voltage V CC = 4.75V I OH = 400μA 2

3.5V V OL Ouptut Low Voltage

V CC = 4.75V I OH = 4mA 0.25

0.4

V I OH

Ouput Source Current - Outputs 1 - 4

V CC = 4.75V

2.75

mA

OSCILLATOR

Symbol Parameter

Test Condtions

Min.Typ.

Max.Unit f osc Frequency Range 5

70

KHz V thL Lower Threshold Voltage 0.33 V CC V V thH Higher Threshold Voltage 0.66 V CC

V R i

Internal Discharge Resistor

0.7

1

1.3

k ?

By substituting equations 1 and 2 into equation 3and solving for the value of R1 the following equa-tions for the external components can be derived :

1

R1 = (– 2) R IN

(4)DC

T1C1 =

(5)

0.69 R1

Looking at equation 1 it can easily be seen that the minimum pulse width of T2 will occur when the value of R1 is at its minimum and the value of R1 at its maximum. Therefore, when evaluating equation 4the minimum value for R1 of 700? (1 K ? – 30 %)should be used to guarantee the required pulse width.

Figure 1 :

Oscillator Circuit and Waveforms.

APPLICATIONS INFORMATION

The circuits shown in figure 2 use the L6506 to im-plement constant current drives for stepper motors.Figure 2 shows the L6506 used with the L298 to drive a 2 phase bipolar motor. The peak current can be calculated using the equation :

V ref

I peak =

R sense The circuit of Fig.2 can be used in applications re-quiring different peak and hold current values by modifying the reference voltage.

The L6506 may be used to implement either full step or half step drives. In the case of 2 phase bipolar stepper motor applications, if a half step drive is used, the bridge requires an additional input to dis-able the power stage during the half step. If used in conjunction with the L298 the enable inputs may be used for this purpose.

For quad darlington array in 4 phase unipolar motor applications half step may be implemented using the 4 phase inputs.

The L6506 may also be used to implement mi-crostepping of either bipolar or unipolar motors.

Figure 2 : Application Circuit Bipolar Stepper Motor Driver. (pin’s number referred to DIP18)

DIP18

DIM.

mm inch MIN.

TYP.

MAX.

MIN.TYP.

MAX.

a10.2540.010

B 1.39

1.65

0.055

0.065

b 0.460.018b10.25

0.010

D 23.24

0.915

E 8.50.335e 2.540.100e320.32

0.800

F 7.10.280I 3.93

0.155

L 3.30.130Z

1.27

1.59

0.050

0.063

OUTLINE AND

MECHANICAL DATA

11011

20

A e

B

D

E L

K

H

A1C

SO20MEC

h x 45?

SO20

DIM.

mm inch

MIN.TYP.MAX.MIN.TYP.MAX.

A 2.35 2.650.0930.104

A10.10.30.0040.012

B0.330.510.0130.020

C0.230.320.0090.013

D12.6130.4960.512

E7.47.60.2910.299

e 1.270.050

H1010.650.3940.419

h0.250.750.0100.030

L0.4 1.270.0160.050

K0? (min.)8? (max.)

OUTLINE AND

MECHANICAL DATA

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