zxbm1015 Zetex Semiconductors plc., zxbm1015 Datasheet - Page 7

• Manufacturer Part Number: zxbm1015
• Description: Variable Speed Single-phase Bldc Motor Controller
• Manufacturer: Zetex Semiconductors plc.

As these threshold voltages are nominally set to V
= 3V and V
follows:
C
Should the fan stop rotating for any reason, i.e. an
obstruction in the fan blade or a seized bearing, then
the device will enter a Rotor Locked condition. In this
condition after a predetermined time (t
will go high and the Phase outputs will be disabled.
After a further delay (t
the Phase drive for a defined period ((t
to re-start the fan. This cycle of (t
repeated indefinitely or until the fan re-starts.
The frequency at which this takes place is determined
by the value of the capacitor applied to this C
For a 12V supply a value of 1uF will typically provide an
'On' (drive) period of 0.56s and an 'Off' (wait) period of
6.8s, giving an On:Off ratio of 1:12.
The C
following equations:
Where:
As these threshold voltages are nominally set to V
= 3V and V
follows:
GND - Ground
This is the device supply ground return pin and will
generally be the most negative supply pin to the fan.
ISSUE 3 - MAY 2007
LCK
- Locked Rotor Timing Capacitor
t
t
t
t
t
t
LCK
PWM
lock
on
off
lock
off
=
=
=
=
=
THL
THL
(
=
V
(
2
V
V
timing periods are determined by the
V
threshold voltages and
I
discharge currents.
3
I
LCKC
xC
I
THH
THH
THH
I
LCKC
PWMC
THH
xC
2
LCKC
I
C
= 1V the equations can be simplified as
= 1V the equations can be simplified as
LCKC
LCK
−
xC
−
LCK
I
V
I
V
LCKC
and V
LCKD
+
and I
THL
THL
LCK
I
PWMD
)
2
)
xC
C
xC
off
LCKD
THL
LCK
) the controller will re-enable
LCK
are the C
are the charge and
t
on
=
off
2
xC
I
LCKC
) and (t
LCK
on
LCK
lock
) in an attempt
pin
) the RD pin
on
LCK
) will be
THH
THH
pin.
7
RD - Locked Rotor Error Output
This pin is the Locked Rotor output as referred to in the
C
stopped and low when it is running.
This is an open collector drive giving an active pull
down with the high level being provided by an external
pull up resistor.
FG - Frequency Generator (speed)
This is the Frequency Generator output and is a
buffered signal from the Hall sensor.
This is an open collector drive giving an active pull
down with the high level being provided by an external
pull up resistor.
Ph1Lo & Ph2Lo - Low-side External H-bridge Driver
These pair of outputs drive the Low side of the external
high power H-bridge devices that in turn drives the
single phase winding. These outputs provide both the
commutation and PWM waveforms. The outputs are of
the Darlington emitter follower type with an active
pull-down to help faster switch off when using bipolar
devices or MOSFET devices with a high gate
capacitance. When in the high state the outputs will
provide up to 80mA of drive into the base or gates of
external transistors as shown in the Typical Application
circuit following.
When in the low state the active Phase drive is capable
of sinking up to 32mA when driving low to aid turn off
times during PWM operation. When the Phase is
inactive the output is held low by a 7.5k
pull-down resistor.
Ph1Hi & Ph2Hi - High-side External H-bridge Driver
These are the High side outputs to the external
H-bridge and are open collector outputs capable of
sinking 100mA. This signal provides commutation only
to the H-bridge.
V+OP- Phase Outputs supply voltage
This pin is the supply to the Phase outputs and will be
connected differently dependant upon external
transistor type.
For bipolar devices this pin will be connected via a
resistor to the VCC pin. The resistor is used to control
the current into the transistor base so its value is
chosen accordingly.
For MOSFET devices the pin will connect directly to the
VCC pin
LCK
timing section above. It is high when the rotor is
ZXBM1015
internal