PBD 3517/1
INH — Inhibit
Purpose of external components
For figures 14 and 15. Note that “Larger than …” is normally the vice versa of “Smaller
than … .”
A HIGH level on the INH input,turns off all
phase outputs to reduce current
consumption.
Component Purpose
Value
Larger than value Smaller than value
Reset
D1, D2
Passes low power to I = 1A
f
motor and prevents
Increases price
Decreases max
current capability
An internal Power-On Reset circuit
connected to Vcc resets the phase logic
and inhibits the outputs during power up,
to prevent false stepping.
1N4001, UF4001
high power from
shorting through low
power supply
D3 … D6
Inductive current
supressor
I = 1A
f
Increases price
Decreases current
turn-off capability
Output Stages
t
= 100nS
Slows down turn- Speeds up turn-
off time. Voltage off time.
at anode might
exceed voltage
breakdown
rr
The output stage consists of four open-
collector transistors. The second high-
voltage supply contains Darlington
transistors.
e.g. BYV27
UF4001
RGPP10G
RGPP30D
R1
Base drive current
limitter
R = 20ohm
Slows down Q1’s Speeds up Q1’s
turn-on and Q4’s turn-on and Q4’s
2
V
mm
P = R1
turn-off time.
turn-off time.
Phase Outputs
The phase outputs are connected directly
to the motor as shown in figure 14.
(
)
R + R
1
2
R2, R3
Base discharge resistor R = 240ohm
V
Slows down Q1’s Speeds up Q1’s
turn-off and Q4’s turn-off and Q4’s
2
mm
P = R1
turn-on time.
)
Decreases ext.
turn-on time.
(
R + R
1
2
R4 … R7 External transistor base
driver
Increases ext.
transistor I max. transistor I max.
V
- V - V
mm be ce
Bilevel Technique
The bilevel pulse generator consists of
two monostables with a common RC
network.
R =
C C
Lowers 3517 Increases 3517
power dissipation. power dissipation.
V
be
I -
4
(
Check hfe.
)
R12
2
P > (I ) • R4
4
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:
R8, R9
ØA, ØB pull-up
resistors
R = 5ohm @ pull-up
Increases noise
sensitivity, worse immunity, better
logic-level logic-level
definition definition.
Increases noise
voltage = 5V.
2
CC
(V
)
P =
R
Less stress on ØA, Stress on ØA, ØB
ØB output output
transistors transistors.
t
On = 0.55 • CT • RT.
See pulse diagrams, figures 16 through
20.
R10, R11 Limit max. motor
current. Resistors may
V
R =
-V
mm Motor CESat
-V
Decreases motor Increases motor
current.
current.
I
Motor max
be omitted. (Check
motor specifications
first.)
Bipolar Phase Logic Output
V
be
R12 … R15 External transistor base
discharge.
Slows down
Speeds up
R =
ª 15
W
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
PA1 and PB1 for phase control, and ØA and
ØB for I0 and I1 control of current turn-off.
external transistor external transistor
turn-off time. turn-off time.
Lowers 3517 Increases 3517
power dissipation power dissipation
I
12
P > V • I
be 12
RT, CT
C1, C2
Sets L and L on time R = 47kohm, C = 10nf Increases on time. Decreases on time.
A B
when triggered by
P < 250mW
STEP.
Stores the doubling
voltage.
C = 100µF
Increases effective Decreases
on-time during effective on-time
voltage doubling during voltage
doubling.
V ≥ 45V
C
C3 … C5
Filtering of supply-
voltage ripple and take-
up of energy feedback
from D3 … D6
C
≥
10 µF
Increases price, Decreases price,
better filtering, more compact
decreases risk of solution.
IC breakdown
Applications Information
V
>V
,V or V Increases price
ss cc
Risk for capacitor
breakdown.
Rated
mm
Logic inputs
Q1, Q2
Q3, Q4
Activation transistor of
voltage doubling.
I
as motor requires. Increases price. Decreases max I
during voltage
doubling.
C
m
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.
- V -V ) • C1
CE
(V
mm
Charging of voltage
doubling capacitor
f
I
=
C
1
- 0.55 • R • C
T
T
(
)
f
Step
Increases max
current capability. current capability.
Q5 … Q8 Motor current drive
transistor.
I
as motor requires.
PNP power trans.
Decreases max
C
Phase outputs
7
ERICSSON [ ERICSSON ]
