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ZXBM2001 ZXBM2002 ZXBM2003
VARIABLE SPEED 2-PHASE FAN MOTOR CONTROLLER
DESCRIPTION
The ZXBM200x is a series of 2-phase, DC brushless motor pre-drivers with PWM variable speed control suitable for fan and blower motors.
FEATURES
* Built in lock detect protection, rotational speed sensing and automatic recovery * Built in Hall amplifier allows direct connection to Hall element * PWM Speed control can be implemented via external voltage or resistance (thermistor) input * Speed (FG) pulse output - ZXBM2003 * Rotor lock output - ZXBM2002 * Combined Rotor Lock (RD) and Speed (FG) signal - ZXBM2001 * Up to 18V input voltage (60V with external regulator) * MSOP10 package
APPLICATIONS
* Mainframe and Personal Computer Fans and Blowers * Instrumentation Fans * Central Heating Blowers * Automotive climate control
ORDERING INFORMATION
DEVICE ZXBM200xX10TA ZXBM200xX10TC REEL SIZE 7" (180mm) 13" (330mm) TAPE WIDTH 12mm 12mm QUANTITY PER REEL 1,000 4,000
Example: ZXBM2001X10TA
DEVICE MARKING
ZXBM2001 - BM21 ZXBM2002 - BM22 ZXBM2003 - BM23
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Absolute maximum ratings
Parameter Supply Voltage Input Current Power Dissipation Operating Temp. Storage Temp. Symbol V CCmax I CC PD T OPR T STG Limits -0.6 to 20 200 500 -40 to 85 -55 to 125 Unit V mA mW C C
Electrical Characteristics (at Tamb = 25C & Vcc = 12V)
Parameter Supply Voltage Supply Current Hall Amp Input Voltage Hall Amp Common Mode Voltage Hall Amp Input Offset Hall Amp Bias Current PH1, PH2 Output High PH1, PH2 Output Off Leakage Current PH1, PH2 Output Current Lock/FG Maximum Collector Voltage Lock/FG Sink Current Lock/FG Low Level O/P Voltage C LCK Charge Current C LCK Discharge Current Lock condition On:Off ratio C LCK High Threshold Voltage C LCK Low Threshold Voltage C PWM Charge Current C PWM Discharge Current PWM Frequency C PWM High Threshold Voltage C PWM Low Threshold Voltage SPD Voltage Control Range SPD Open Circuit Voltage V THH V THL I PWMC I PWMD F PWM V THH V THL V SPD 1 1.5 3.6 50 V CM V OFS V BS V OH I OFF I OL V OH I OL V OL I LCKC I LCKD -1.8 V CC -2.2 Symbol V CC I CC 40 0.5 0.5V CC 7 -350 V CC -1.8 10 80 V CC 5 0.3 -2.8 0.28 1:7 1:10 2.0 1.0 4.3 62 24 2.0 1.0 2 5.0 75 V V A A kHz V V V V 2 3 V in = 1.5V V in = 1.5V C PWM = 0.15nF 0.35 0.5 V CC -1.5 Min 4.5 2.2 Typ Max 18 3.25 Unit V mA mV V mV nA V A mA V mA V A A I OL = 5mA V in = 1.5V V in = 1.5V I OH = 80mA No Load 1 diff p-p Conditions
Notes: 1 Measured with pins H+, H-, CLCK and CPWM = 0V and all other signal pins open circuit. 2 The 1V minimum represents 100% PWM drive and 2V represents 0% PWM drive. 3 This voltage is determined by an internal resistor network of 52.5k from the pin to Gnd and 19.5k resistors track each other the absolute values are subject to a 20% manufacturing tolerance.
from the pin to a 2V reference. Whilst both
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Block Diagram (ZXBM2001):
Pin Assignments
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Pin Functional Descriptions
1. VCC - Applied voltage 5. GND - Ground
This is the device supply voltage. For 5V to 12V fans this can be supplied directly from the Fan Motor supply. For fans likely to run in excess of the 18V maximum rating for the device this will be supplied from an external regulator such as a zener diode. 2. H+ 3. H- Hall input - Hall input
This is the device supply ground return pin and will generally be the most negative supply pin to the fan. 6. LOCK/FG - Locked Rotor error output / Frequency Generator (speed) output On the ZXBM2001 the Lock/FG pin is designed to be a dual function pin to provide an indication of the Fans rotational speed together with an indication of when the Fan has failed rotating for whatever reason (Rotor Locked condition). The pin is an open collector drive, that is there is an active pull down with the high level being provided by an external pull up resistor. Under correct operating conditions, and with this external pull-up in place, this pin will provide an output signal whose frequency will be twice that of the rotational frequency of the fan. Should the fan itself 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 the Lock/FG pin will go high (regardless of the state of the Hall sensor) when the CLCK pin reaches the VTHH threshold and will remain high until the fan blades start rotating again. On the ZXBM2002 variant this pin is Lock. During normal operation the signal will be low and during a Locked Rotor condition the pin will go high when the CLCK pin reaches the VTHH threshold. For the ZXBM2003 variant this pin is FG. This signal is a buffered and inverted output of the Hall signal and therefore provides an output signal whose frequency will be twice that of the rotational frequency of the fan. 7. CLCK - Locked Rotor timing capacitor
The rotor position of the Fan Motor is detected by a Hall sensor whose output is applied to these pins. This sensor can be either a 4 pin `naked' Hall device or a 3 pin buffered switching type. For a 4 pin device the differential Hall output signal is connected to the H+ and H- pins. For a 3 pin buffered Hall sensor the Hall device output is attached to the H+ pin whilst the H- pin has an external potential divider attached to hold the pin at half VCC. When H+ is high in relation to H- Ph2 is the active drive. 4. SPD - Speed control voltage input
This pin provides control over the Fan Motor speed by varying the Pulse Width Modulated (PWM) drive ratio at the Ph1 and Ph2 outputs. This control signal can take the form of either a voltage input of nominal range 2V to 1V, representing 0% to 100% drive respectively, or alternatively a thermistor can be attached to this pin to control the voltage. The pin has an internal potential divider between Gnd and an internal 2.0V reference designed to hold the pin at approximately 1.5V. This will represent a drive of nominally 50%. The addition of a 100k NTC thermistor to ground, for example, will provide a drive nominally 70% at 25C and 100% at 50C. If speed control is not required this pin is can be left open circuit for 50% drive or tied to ground by a 10k resistor to provide 100% drive. If required this pin can also be used as an enable pin. The application of a voltage of 2.0V to VCC will to force the PWM drive fully off, in effect disabling the drive.
When in a Locked Rotor condition as described above the Ph1 and Ph2 drive outputs go into a safe drive mode to protect the external drive devices and the motor windings. This condition consists of driving the motor for a short period then waiting for a longer period before trying again. The frequency at which this takes place is determined by the size of the capacitor applied to this CLCK pin. For a 12V supply a value of 1.0uF will typically provide an `On' (drive) period of 0.33s and an `Off' (wait) period of 4.0s, giving an On:Off ratio of 1:12.
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Locked Rotor timing capacitor (CONT). The CLCK timing periods are determined by the following equations: VTHH x CLCK ILCKC Ton = (VTHH - VTHL) x CLCK ILCKD 9. PH2 10. PH1 - External transistor driver - External transistor driver
Tlock =
Toff =
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.
(VTHH - VTHL) x CLCK ILCKC
Lock and FG Timing Waveform:
Where VTHH and VTHL are the CLCK pin threshold voltages and ILCKC and ILCKD are the charge and discharge currents. As these threshold voltages are nominally set to VTHH=2V and VTHL=1V the equations can be simplified as follows: Tlock = 2 x CLCK ILCKC Ton = CLCK ILCKC Toff = CLCK ILCKD
8. CPWM - Sets PWM frequency 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 CLCK timing period (Tpwm) is determined by the following equation: (VTHH - VTHL) x CPWM (VTHH - VTHL) x CPWM + IPWMC IPWMD Lock Timing Example: Using the equation previously described and to be found under the CLCK pin description: Tlock = Where VTHH and VTHL are the CPWM pin threshold voltages and IPWMC and IPWMD are the charge and discharge currents. As these threshold voltages are nominally set to VTHH=2V and VTHL=1V the equations can be simplified as follows: CPWM CPWM + IPWMC IPWMD 2 x CLCK ILCKC Ton = CLCK ILCKC Toff = CLCK ILCKD
Tpwm =
Using a value of CLCK = 1.0uF together with the values of ILCKC and ILCKD to be found in the Electrical Characteristics we can derive the following timings for operation at 12V and 25C. 2 x 1.0 F = 0.714s 2.8 A Ton = 1.0 F = 3.6s 0.28 A
Tlock = Tpwm =
Toff =
2 x 1.0 F = 0.36s 2.8 A
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APPLICATION INFORMATION
The ZXBM200x series of 2-phase DC brushless motor pre-drivers are capable of driving both Bipolar or MOSFET power transistors. For smaller fans and blowers it is likely that bipolar power transistors would be used as shown in the following Applications circuit. In Figure 1, R1 & R2 have their value selected to provide suitable base current in keeping with the winding current and gain of the power transistors Q1 & Q2. R3 & R4 have their value selected to provide efficient switch-off of Q1 & Q2. The Zener diodes ZD1 & ZD2 provide active clamping in conjunction with Q1 & Q2. It is also recommended that the supply de-coupling capacitor C3 is positioned as close as is practical to the ZXBM device pins. Also illustrated in the two Applications circuits above are the methods of connection for both a `naked' Hall device, as seen in the bipolar circuit in Figure 1, and a buffered Hall device, as in the MOSFET circuit in Figure 2. In this latter circuit R5 & R6 bias the H- pin at a voltage equivalent to half the swing of the Hall device. R7 will be needed if the buffered Hall device does not have its own internal pull-up.
TYPICAL APPLICATION (ZXBM2001) using MOSFET power transistors
TYPICAL APPLICATION (ZXBM2001) using Bipolar power transistors
Figure 2 Graph 1 below, illustrates the PWM drive waveform taken from and application using the MOSFET circuit in Figure 2. This shows the waveforms to be found at the Ph1 output and at the drain/Winding node.
Figure 1 In the case of higher power fans and blowers it may be more applicable to use MOSFET devices to switch the windings as illustrated in the second applications circuit shown in Figure 2. In Figure 2, the Resistor ratio of R1 to R3 and R2 to R4 provide the required Gate turn-on voltage whilst the absolute values will be chosen to provide sufficient gate switching currents.
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When driving fans with bipolar transistors, at higher voltages it may be necessary to provide extra noise protection by the addition of a diode from the driver collector to Gnd on each phase. This prevents negative voltage excursions from the windings affecting operation. See Figure 3 right, showing the placement of these diodes. It should be noted that these are not required for the MOSFET solution in Figure 2 as the diodes are inherent in the MOSFET structure. Zetex provide a variety of suitable power transistors for using with the ZXBM200x series of 2-phase DC brushless motor pre-drivers and suitable devices sufficient for a range of applications are given in the following table.
TYPICAL APPLICATION (ZXBM2001) illustrating addition of Clamp diodes.
Figure 3
SUMMARY TABLE OF SUITABLE DEVICES
Bipolar Types V CEO (V) I C (A) min H FE @ I C V CE(sat) max (mV) @ IC & IB Package
FZT1053A FZT851 ZXT13N50DE6
75 60 50
4.5 6 4
300 @ 0.5A 100 @ 2A 300 @ 1A
200@1A,10mA 100@1A,10mA 100@1A,10mA
SOT223 SOT223 SOT23-6
MOSFET Types
BV DSS (V)
I D (A)
I PEAK (A) (Pulsed)
R DS(on) (mW) @ V GS 20 @ 10V 45 @ 10V
Package
ZXMN3A04DN8 2 ZXMN6A09DN8
3
30 60
7.6 5
25 17.6
SO8 SO8
23
Notes: 1 Contact your nearest Zetex office for further details and technical enquiries. 2 Dual device 3 Provisional information 4 Advanced information
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PACKAGE DIMENSIONS
DIM A A1 A2 D E E1 b c e
MILLIMETRE MIN. MAX. 1.10 0.15 0.75 0.95
3.00 BSC 4.90 BSC 3.00 BSC 0.17 0.08 0.27 0.23
0.50 BSC 0 15 0.80
L L1
0.40
0.95 BSC
Conforms to JEDEC MO-187 VARIATION BA
(c) Zetex plc 2002
Zetex plc Fields New Road Chadderton Oldham, OL9 8NP United Kingdom Telephone (44) 161 622 4422 Fax: (44) 161 622 4420 Zetex GmbH Streitfeldstrae 19 D-81673 Munchen Germany Telefon: (49) 89 45 49 49 0 Fax: (49) 89 45 49 49 49 Zetex Inc 700 Veterans Memorial Hwy Hauppauge, NY11788 USA Telephone: (631) 360 2222 Fax: (631) 360 8222 Zetex (Asia) Ltd 3701-04 Metroplaza, Tower 1 Hing Fong Road Kwai Fong Hong Kong Telephone: (852) 26100 611 Fax: (852) 24250 494
These offices are supported by agents and distributors in major countries world-wide. This publication is issued to provide outline information only which (unless agreed by the Company in writing) may not be used, applied or reproduced for any purpose or form part of any order or contract or be regarded as a representation relating to the products or services concerned. The Company reserves the right to alter without notice the specification, design, price or conditions of supply of any product or service. For the latest product information, log on to
www.zetex.com
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