ZXBM2004 VARIABLE SPEED 2-PHASE FAN MOTOR CONTROLLER FOR THERMISTOR CONTROL DESCRIPTION The ZXBM2004 is a 2-phase, DC brushless motor pre-driver with PWM variable speed control suitable for fan and blower motors. The controller is primarily intended for thermal control using a thermistor but can also be used for control using an external voltage or PWM signal. FEATURES SO14 * PWM Speed control via external thermistor * Ability to be able to set a minimum speed * Ability to be able to remove any speed change against supply voltage variation * Low noise * Built in lock detect protection, rotational speed sensing and automatic recovery * Built in Hall amplifier allows direct connection to Hall element * Speed (FG) pulse output * Rotor lock (RD) output * Up to 18V input voltage (60V with external regulator) * SO14N and QSOP16 package options APPLICATIONS * Mainframe and Personal Computer Fans and Blowers QSOP16 * Instrumentation Fans * Central Heating Blowers * Automotive climate control ORDERING INFORMATION - SO14N DEVICE REEL SIZE TAPE WIDTH QUANTITY PER REEL ZXBM2004N14TA 7" (180mm) 16mm 500 ZXBM2004N14TC 13" (330mm) 16mm 2,500 ORDERING INFORMATION - QSOP16 DEVICE REEL SIZE TAPE WIDTH QUANTITY PER REEL ZXBM2004Q16TA 7" (180mm) 12mm 500 ZXBM2004Q16TC 13" (330mm) 12mm 2,500 DEVICE MARKING ZETEX ZXBM2004 Date code PROVISIONAL ISSUE E - APRIL 2003 1 SEMICONDUCTORS ZXBM2004 ABSOLUTE MAXIMUM RATINGS PARAMETER SYMBOL LIMITS UNIT Supply Voltage V CCmax -0.6 to 20 V Input Current I CCmax 200 mA Power Dissipation P Dmax 500 mW Operating Temp. T OPR -55 to 110 C Storage Temp. T STG -55 to 125 C ELECTRICAL CHARACTERISTICS (at Tamb = 25C & Vcc = 12V) PARAMETER SYMBOL MIN 4 Supply Voltage V CC Supply Current I CC Hall Amp Input Voltage V IN 40 Hall Amp Common Mode Voltage V CM 0.5 Hall Amp Input Offset V OFS TYP 5 MAX UNIT 18 V 6.8 mA No Load 1 mV diff p-p Vcc-1.5 7 V mV 350 nA V CC -1.8 V I OH =80mA 0.6 V I OL =20mA 2 0.6 V I OL =50A 3 -80 mA Hall Amp Bias Current I BS PH1, PH2 Output High V OH PH1, PH2 Output Low V OLA 0.4 PH1, PH2 Output Low V OLB 0.4 PH1, PH2 Output Source Current I OH V CC -2.2 CONDITIONS PH1, PH2 Output Sink Current I OL 20 mA C PWM Charge Current I PWMC -3.6 -4.3 -5.0 A C PWM Discharge Current I PWMD 50 62 75 C PWM High Threshold Voltage V THH 1 V C PWM Low Threshold Voltage V THL 2 V PWM Frequency F PWM 24 kHz C PWM = 0.15nF ThRef Voltage V ThReF 1.94 V I OL =100A S MIN Output Current I OSMIN -25 SPD Voltage Minimum V SPDL 1 V 100% PWM Drive SPD Voltage Maximum V SPDH 2 V 0% PWM Drive SPD Open Circuit Voltage V SPDOC 1.5 V 4 C LCK Charge Current I LCKC -3.8 A -3.0 1.96 2 -30 -35 A A C LCK Discharge Current I LCKD -0.38 C LCK High Threshold Voltage V THH 1 V C LCK Low Threshold Voltage V THL 2 V Lock condition On:Off ratio -0.45 A 1:10 Notes: 1. Measured with pins H+, H-, CLCK and CPWM = 0V and all other signal pins open circuit. 2. Measured when opposing Phase Output is Low 3. Measured when opposing Phase Output is High 4. This voltage is determined by an internal resistor network of 52.5K from the pin to Gnd and 19.5K from the pin to a 2V reference. The resistor values are subject to a 20% manufacturing tolerance. PROVISIONAL ISSUE E - APRIL 2003 SEMICONDUCTORS 2 ZXBM2004 BLOCK DIAGRAM PIN ASSIGNMENTS H+ Vcc 1 H+ V+OP H- Vcc 1 V+OP HThRef Ph1 SPD ThRef Ph2 SPD SOIC14 CPWM FG SMIN RD Gnd CLCK Ph1 N/C ZXBM2004 ZXBM2004 Ph2 QSOP16 N/C CPWM FG SMIN RD Gnd CLCK PROVISIONAL ISSUE E - APRIL 2003 3 SEMICONDUCTORS ZXBM2004 PIN FUNCTIONAL DESCRIPTION H+ H- - Hall input - Hall input If speed control is not required this pin can be left open circuit for 50% drive or tied to ground to provide 100% drive. The rotor position 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 of the 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 buffered Hall sensor the Hall device output is attached to the H+ pin, with a pull-up attached if needed, 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. If required this pin can also be used as an enable pin. The application of a voltage >2.0V will to force the PWM drive fully off, in effect disabling the drive. 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. ThRef - Thermistor network reference This is a reference voltage of nominal 1.96V. It is designed for the ability to 'source' current into the thermistor network therefore it will not 'sink' any current from a higher voltage. The CLCK timing period (TPWM) is determined by the following equation: TPWM = SPD - Thermistor network input The thermistor network is attached to this pin. The resultant thermistor network voltage applied to the SPD pin provides control over the Fan Motor speed by varying the Pulse Width Modulated (PWM) drive ratio at the Ph1 and Ph2 outputs. The control signal takes the form of a voltage input of range 2V to 1V, representing 0% to 100% drive respectively. Where: (V THH - VTHL ) x C IPWMC V - VTHL ) x C + ( THH IPWMD C = CPWM +15 - in pF VTHH and VTHL are the CPWM pin threshold voltages IPWMC and IPWMD are the charge and discharge currents in A. TPWM in S As these threshold voltages are nominally set to VTHH = 2V and VTHL = 1V the equations can be simplified as follows: In normal operation a 10k NTC thermistor network as shown in the Block Diagram would be attached to the SPD pin, however for simplicity of use it is possible to attach an 100k NTC thermistor directly to the pin. The pin has an internal potential divider between Gnd and an internal 1.96V reference designed to hold the pin at approximately 1.5V. This will represent a drive of nominally 50%. The addition of the 100k NTC thermistor from the SPD pin to ground will provide a drive nominally 70% at 25C and 100% at 50C. TPWM = C C + IPWMC IPWMD SMIN - Sets Minimum Speed When using a thermistor to control a fan's speed it is possible that at low temperatures the fan might fail to start or if already running and the temperature drops the fan might stop. This is an undesirable condition to have in thermal controlled fans so the SMIN pin is used to set a minimum speed. The following graph illustrates a typical speed response characteristic for a thermally controlled fan. PROVISIONAL ISSUE E - APRIL 2003 SEMICONDUCTORS 4 ZXBM2004 Fan speed (%) GND - Ground 10 0 90 80 70 60 50 Set Minimum Speed 40 30 20 10 0 -10 0 10 20 30 This is the device supply ground return pin and will generally be the most negative supply pin to the fan. CLCK - Locked Rotor timing capacitor 40 50 60 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 (TLOCK) the RD pin will go high and the Phase outputs will be disabled. After a further delay (TOFF) the controller will re-enable the Phase drive for a defined period (TON) in an attempt to re-start the fan. This cycle of (TOFF) and (TON) will be repeated indefinitely or until the fan re-starts. 70 Temperature (C) 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 1uF will typically provide an 'On' (drive) period of 0.26s and an 'Off' (wait) period of 2.6s, giving an On:Off ratio of 1:10. Typical Temperature Response When a resistor is attached from this pin to Gnd it sets a voltage on the pin. This voltage is monitored by the SPD pin such that it cannot rise above it. As a higher voltage on the SPD pin represents a lower speed it therefore restricts the lower speed range of the fan. If this feature is not required the pin is left open circuit so no minimum speed will be set. The C LCK timing periods are determined by the following equations: TLOCK = VTHH x C LCK lLCKC If the fan is being controlled from an external voltage source either this feature should not be used or if it is required then a >1k resistor should be placed in series with the SPD pin. TOFF = Where: The following equation is used to set the voltage on the SPD pin and thus minimum speed. Note that the actual minimum speed will be a function of the motor mechanics. THH (V THH - VTHL )x C LCK ILCKC - VTHL )x C LCK ILCKD 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: VSMIN = IOSMIN x RSMIN Where: (V TON = VSMIN is the voltage on pin SMIN that represents the maximum voltage on the SPD pin in turn representing the minimum speed. IOSMIN is in mA RSMIN is in k and VSMIN is in V TLOCK = 2 x C LCK ILCKC TON = C LCK ILCKC TOFF = C LCK ILCKD PROVISIONAL ISSUE E - APRIL 2003 5 SEMICONDUCTORS ZXBM2004 RD - Locked Rotor error output VCC This pin is the Locked Rotor output as referred to in the CLCK timing section above. It is high when the rotor is stopped and low when running. - Applied voltage This is an open collector drive giving an active pull down with the high level being provided by an external pull up resistor. This is the device internal circuitry 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. FG RD and FG Timing Waveform: - Frequency Generator (speed) output 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. PH1 PH2 - Phase 1 External transistor driver - Phase 2 External transistor driver These are the Phase drive outputs and are darlington emitter follower outputs with an active pull-down to help faster switch off when using bipolar devices. The outputs are designed to provide up to 80mA of drive when high to the base or gates of external transistors as shown in the Typical Application circuit following. The external transistors in turn drive the fan motor windings. Lock Timing Example: In addition the active Phase drive is capable of sinking up to 20mA when driving low to aid turn off times during PWM operation. When the Phase is inactive the output is held low by an internal pull-down resistor Using the equation previously described and to be found under the CLCK pin description: TLOCK = 2 x C LCK ILCKC TON = C LCK ILCKC TOFF = C LCK ILCKD V+OP - Phase Outputs supply voltage Using a value of CLCK = 1.0uF together with the values of I LCKC and I LCKD to be found in the Electrical Characteristics we can derive the following timings for operation at 12V and 25C: 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 by a resistor to the VCC pin. The resistor is used to control the current into the transistor base so its value is chosen accordingly. TLOCK = 2 x 1uF = 0.526s 3.8A TOFF = For MOSFET devices the pin will connect to the VCC pin TON = 1uF = 0.236s 3.8A 1uF = 263 . s 0.38 A PROVISIONAL ISSUE E - APRIL 2003 SEMICONDUCTORS 6 ZXBM2004 APPLICATIONS INFORMATION Figure 1 shows an Application Circuit for driving bipolar devices. The normal practice when driving a bipolar device would be to use a base series resistor to control and limit the current into the base. However the problem with this would be that the resistor would also restrict the removal of the base stored charge at switch-off. In order to keep turn-off times as short as possible it is therefore preferable to remove the base resistor and apply the current limiting in the supply to the output stage. This is not too dissimilar from the approach taken by conventional Totem-pole output stages in TTL devices. This section is intended to give a brief insight into using the ZXBM2004. More complete data covering all applications aspects of this and other ZXBM series of fan motor pre-drivers is available from the Zetex website www.zetex.com or from your nearest Zetex office. The ZXBM2004 device is a development of the ZXBM2001 to ZXBM2003 series of fan motor controller that has been specifically developed for use in thermistor temperature control situations. The main feature of the device is the ability to set a minimum speed at which the fan will run. In the case of the ZXBM2004 the current limiting is applied by inserting a resistor from V+OP to the VCC pin. The current applied to the base is determined by: Two application circuits are illustrated here and both show slightly differing ways in which the ZXBM2004 controller can be used. For example Figure 1 employs bipolar driver transistors and a naked Hall device whilst the Figure 2 employs MOSFET devices, a buffered Hall device and speed vs supply change normalisation. These differing features will be described in detail in the following sections. V + 0.7) R5 = VCC - ( OH IOut Where: The Phase Outputs The Phase outputs on the ZXBM2004 2-phase DC brushless motor pre-driver have been designed to be capable of driving both Bipolar or MOSFET power transistors. The output stage consists of both active pull-up and active pull-down devices for optimum PWM switching. Pulling up, the output can deliver a maximum of 80mA whilst pulling down, sinking 20mA is possible. This is particularly useful for driving bipolar devices where for fast turn-off it is important to remove base stored charge as quickly as possible. VOH is the Phase Drive Output High Voltage. IOut is the drive required to the external Phase Drive transistors The circuit example in Figure 1 has the external drive (IOut) set to 34mA. PROVISIONAL ISSUE E - APRIL 2003 7 SEMICONDUCTORS ZXBM2004 D2 12V D1 1N4004 1N4148 W2 W1 R8 2k 280 R3 H+ VCC H- V+OP Hall R6 ThRef ZXBM2004 SPD C4 R5 ZD2 47V Q2 FCX 1053A Ph2 CPWM FG SMIN RD 0.1F 3.3k Q1 FCX 1053A Ph1 2k RTherm 10k NTC C5 2.2F ZD1 47V C3 CLCK 1F Gnd R4 39k C2 150pF C1 FG 1F RD 0V Figure 1: Typical Application Circuit utilising Bipolar power transistors and a Naked Hall device. The V+OP pin will then be connected directly to the supply i.e. the Vcc pin. Figure 2 illustrates this. When driving MOSFETs a more conventional approach is employed in that each MOSFET will have a gate limiting resistor to control turn-on and turn-off. D2 12V D1 1N4004 1N4148 W2 W1 R8 33k R7 100k R9 33k H+ VCC H- V+OP Hall R6 ThRef 1.6k SPD RTherm 10k NTC C4 R10 33k 0.1F R5 3.3k ZD1 47V D3 1N4148 R1 Ph1 ZXBM2004 100 C5 2.2F Q2 Q1 ZXMN ZXMN 6A07Z 6A07Z ZD2 47V D4 1N4148 R2 100 Ph2 CPWM FG SMIN RD C3 C2 150pF CLCK 1F Gnd R4 43k C1 FG 1F RD 0V Figure 2: Typical Application Circuit utilising MOSFET power transistors and a bufferred Hall device. PROVISIONAL ISSUE E - APRIL 2003 SEMICONDUCTORS 8 ZXBM2004 Thermal Control Minimum Speed The ZXBM2004 has been specifically designed for use in thermal control applications where a thermistor is employed for temperature sensing. One of the main features of the ZXBM2004 is the ability to set a minimum speed that the fan will run. This will avoid the fan stopping at low temperatures and also ensures the fan will always start when cold. The simplest way in which the controller can be used is by attaching a 100k NTC thermistor between the SPD pin and ground and in which case the controller's own pre-set temperature characteristics will be used. Pin SMIN is used to set the minimum speed and simply consists of a resistor from the pin to ground. A current forced from this pin through the resistor will give a volt drop that represents the voltage on the SPD pin that will in turn represent the minimum speed. In most applications however, it is expected that the user will wish to set their own temperature response characteristics. To do this a 10k NTC thermistor can be employed in conjunction with a pair of resistors to set such parameters as the speed at 25C and the slope of the response up to full speed. The best approach to set up a fan for this feature is to run the fan at the desired minimum speed, measure the voltage on the SPD pin and set that voltage using the equation shown in the Pin Description section. It might be found in practice that the E24 series of resistors results in too course a change. In this situation the E48 series or 2 resistors in parallel or in series will give more control over the precise minimum speed. R5 and R6 in both figures are used to set the temperature response. The ratio between the two resistors will enable the user to set the speed of the fan at 25C. This is influenced by the mechanical response of the fan and also by the inductance of the stator windings so the resistor ratio needs to be adjusted by trial to take this into account. If the minimum speed feature is not required the pin is left open circuit. Speed vs Supply Change Normalisation The ratio of R5 compared to the 10kof the thermistor will determine the slope. Raising the value of R5 in relation to the Thermistor will give a steeper slope, for example say 50% speed at 25C and full speed at 40C, whereas lowering the value will make the slope shallower, for example 50% speed at 25C and full speed at 55C. With the ZXBM2004, and by the addition of one resistor, it is possible to set the thermistor network so as the fan's speed remains constant when the supply voltage changes. This is very useful where a fan is to be specified over a large supply voltage range. Figure 2 illustrates a circuit where the feature is included. In this case resistor R7 is added into the thermistor network between the supply and the SPD pin. The value chosen for R7 will be dependant upon the fan's characteristics but will be typically around 100k. The precise value is best determined by trial but it should be pointed out that in order to keep the same temperature response characteristics the value of R6 will also need to be increased in compensation as the two resistors are in effect in parallel. PROVISIONAL ISSUE E - APRIL 2003 9 SEMICONDUCTORS ZXBM2004 External Voltage and PWM control Where control is required using an externally generated PWM signal the SPD pin should be left open circuit and the PWM signal applied to the CPWM pin. The signal can be a conventional 5V or 3.3V TTL or CMOS compatible waveform. As an alternative to control by a thermistor it is also possible to control the speed of the fan by a signal from an external source. This signal may be either a control voltage or PWM waveform signal. When a voltage signal is used it will be applied to the SPD pin and should vary between 1V representing full speed (100% PWM drive) and 2V representing 0% PWM drive. In practice, and dependant upon the other aspects of the motor design, low speed might be represented by 50% PWM drive. If the Minimum Speed feature is required then the signal should be applied to the ZXBM2004 SPD pin via a 2.2k resistor to allow the internal minimum speed circuit to over-ride the control voltage. A Selection of Suitable Transistors and MOSFETs Bipolar Types (NPN) V CEO (V) I C (A) Min H FE @ I C FCX1053A 75 4.5 300 @ 0.5A 200 @ 1A / 10mA SOT89 FZT851 60 6 100 @ 2A 100 @ 1A / 10mA SOT223 FZT853 100 6 100 @ 2A 175 @ 1A / 100mA SOT223 FZT855 150 4 100 @ 1A 65 @ 0.5A / 50mA SOT223 50 4 300 @ 1A 100 @ 1A / 10mA SOT23-6 ZXT13N50DE6 MOSFET Types (N-channel) V DS (V) I D (A) ZXMN3A04DN8 1 30 ZXMN6A09DN8 1 2 60 ZXMN6A07F 60 V CE(sat) max(mV) @ IC / IB I PEAK (A) (Pulsed) R DS(on) max(mW) @ V GS 7.6 25 20 @10V 5 17.6 45@10V 1 4 45 @ 10V Package Package SO8 (DUAL SO8 (DUAL) SOT23 ZXMN6A11Z 60 3.8 10 140@10V SOT89 ZXMN6A11G 60 3.8 10 140@10V SOT223 100 1.9 5.9 600@10V SOT223 ZXMN10A11G PROVISIONAL ISSUE E - APRIL 2003 SEMICONDUCTORS 10 ZXBM2004 PACKAGE DIMENSIONS PACKAGE OUTLINE SO14N DIM A A1 D H E L e b c h PACKAGE OUTLINE QSOP16 MIN. MAX. 1.35 1.75 0.10 0.25 8.55 8.75 5.80 6.20 3.80 4.00 0.40 1.27 1.27 BSC 0.33 0.51 0.19 0.25 0 8 0.25 0.50 PACKAGE DIMENSIONS DIM A A1 A2 D ZD E E1 L e b c h Note: MILLIMETRE INCHES MIN. MAX. 0.053 0.069 0.004 0.010 0.337 0.344 0.228 0.244 0.150 0.157 0.016 0.050 0.050 BSC 0.013 0.020 0.008 0.010 0 8 0.010 0.020 MILLIMETRE INCHES MIN. MAX. 0.053 0.069 0.004 0.010 0.049 0.059 0.189 0.197 0.009 Ref 0.228 0.244 0.150 0.157 0.016 0.050 0.025 BSC 0.008 0.012 0.007 0.010 0 8 0.010 0.020 MIN. MAX. 1.35 1.75 0.10 0.25 1.25 1.50 4.80 5.00 0.23 BSC 5.79 6.20 3.81 3.99 0.41 1.27 0.64 BSC 0.20 0.30 0.18 0.25 0 8 0.25 0.50 Dimensions in Inches are Control Dimensions dimensions in millimetres are approximate (c) Zetex plc 2003 Americas Asia Pacific Zetex GmbH Streitfeldstrae 19 D-81673 Munchen Zetex Inc 700 Veterans Memorial Hwy Hauppauge, NY 11788 Germany Telefon: (49) 89 45 49 49 0 Fax: (49) 89 45 49 49 49 europe.sales@zetex.com USA Telephone: (1) 631 360 2222 Fax: (1) 631 360 8222 usa.sales@zetex.com Zetex (Asia) Ltd 3701-04 Metroplaza Tower 1 Hing Fong Road Kwai Fong Hong Kong Telephone: (852) 26100 611 Fax: (852) 24250 494 asia.sales@zetex.com Europe Zetex plc Fields New Road Chadderton Oldham, OL9 8NP United Kingdom Telephone (44) 161 622 4444 Fax: (44) 161 622 4446 hq@zetex.com 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 PROVISIONAL ISSUE E - APRIL 2003 11 SEMICONDUCTORS