ZXBM2001 Zetex Semiconductors, ZXBM2001 Datasheet - Page 5

• Manufacturer Part Number: ZXBM2001
• Description: VARIABLE SPEED 2-PHASE FAN MOTOR CONTROLLER
• Manufacturer: Zetex Semiconductors

Locked Rotor timing capacitor (CONT).
The C
following equations:
Where V
voltages and I
discharge currents.
As these threshold voltages are nominally set to
V
as follows:
8. C
This pin has an external capacitor attached to set the
PWM frequency for the Phase drive outputs. A
capacitor value of 0.15nF will provide a PWM
frequency of typically 24kHz.
The C
following equation:
Where V
voltages and I
discharge currents.
As these threshold voltages are nominally set to
V
as follows:
ISSUE 1 - APRIL 2002
THH
THH
T
lock
T
PWM
lock
T
=2V and V
=2V and V
LCK
pwm
LCK
V
THH
THH
THH
2
- Sets PWM frequency
timing period (T
I
I
LCKC
LCKC
timing periods are determined by the
(
C
V
C
LCK
THH
and V
and V
PWMC
LCK
LCKC
THL
THL
T
on
T
I
V
PWMC
=1V the equations can be simplified
=1V the equations can be simplified
pwm
THL
THL
THL
(
and I
and I
V
)
T =
THH
on
I
C
are the C
C
PWMC
are the C
PWM
PWM
pwm
LCKD
PWMD
C
I
I
V
LCKC
LCKC
LCK
THL
T
) is determined by the
(
I
off
)
C
PWMD
V
PWM
are the charge and
THH
C
are the charge and
PWM
LCK
(
LCK
V
THH
I
V
PWMD
THL
pin threshold
pin threshold
T
)
I
V
LCKD
off
THL
C
PWM
)
C
I
LCKD
LCK
C
LCK
5
9. PH2
10. PH1
These are the Phase drive outputs and are open
darlington emitter followers designed to provide up to
80mA of drive to external transistors as shown in the
Application circuits following. The external transistors
in turn drive the fan motor windings.
Lock and FG Timing Waveform:
Lock Timing Example:
Using the equation previously described and to be
found under the C
Using a value of C
of I
Characteristics we can derive the following timings for
operation at 12V and 25°C.
T
T
LCKC
lock
lock
=
ZXBM2001
ZXBM2002 ZXBM2003
2 1.0 F
- External transistor driver
- External transistor driver
2
and I
2.8 A
I
LCKC
C
LCK
LCKD
T =
on
LCK
LCK
0 714
.
2 1.0 F
= 1.0uF together with the values
pin description:
to be found in the Electrical
2.8 A
T
on
s
C
I
LCKC
LCK
T =
0 36
off
.
s
0.28 A
1.0 F
T
off
C
I
LCKD
3 6 . s
LCK