UC1620 UC3620 Switchmode Driver for 3-∅ Brushless DC Motors FEATURES DESCRIPTION • 2A Continuous, 3A Peak Output Current • 8V to 40V Operation • Internal High Gain Amplifier for Velocity Control Applications • TTL Compatible Hall Inputs • Mask Programmable Decode Logic The UC3620 is a brushless DC motor driver capable of decoding and driving all 3 windings of a 3-phase brushless DC motor. In addition, an on-board current comparator, oscillator, and high gain Op-Amp provide all necessary circuitry for implementing a high performance, chopped mode servo amplifier. Full protection, including thermal shutdown, pulse-by-pulse current limiting, and under-voltage lockout aid in the simple implementation of reliable designs. Both conducted and radiated EMI have been greatly reduced by limiting the output dv/dt to 150V/µs for any load condition. • Pulse-by-Pulse Current Limiting • Internal Thermal Shutdown Protection • Under-Voltage Lockout • Available in SP Hermetic Package The UC1620SP is characterized for operation over the full military temperature range of -55°C to +125°C, while the UC3620SP is characterized for 0°C to +70°C. BLOCK DIAGRAM 3/97 1 UC1620 UC3620 ABSOLUTE MAXIMUM RATINGS (Note 1) CONNECTION DIAGRAMS Supply Voltage, VCC . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 40V Output Current, Source or Sink Non-Repetitive (t = 100µsec), lo . . . . . . . . . . . . . . . . . . . . 3A Repetitive (80% on - 20% off; tON = 10ms) . . . . . . . . . . 2.5A DC Operation. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2A Analog Inputs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . -0.3 to +Vcc Logic Inputs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . -0.3 to +Vcc Total Power Dissipation (at TCASE = 75° C) for SP Package (Note 2). . . . . . . . . . . . . . . . . . . . . . . . . . 15W Storage Temperature . . . . . . . . . . . . . . . . . . . . -65°C to +150°C Operating Junction Temperature . . . . . . . . . . . -55°C to +150°C SP Hermetic Power DIL Note 1: All voltages are with respect to ground. Currents are positive into, negative out of the specified terminal. Note 2: Consult Packaging Section of Databook for thermal limitations and considerations of package. ELECTRICAL CHARACTERISTICS: Unless otherwise stated, these specifications apply for TA = 0°C to 70°C for 3620; TA = 55°C to +125°C for UC1620; VCC = 20V, RT = 20V, RT = 10k, CT = -2.2nF. TA=TJ. PARAMETER TEST CONDITIONS UC3620 MIN UC1620 TYP MAX Input Offset Voltage 1.5 Input Bias Current Input Offset Current MIN UNIT TYP MAX 10 1.5 10 -.25 -2.0 -.25 -2.0 µA 15 250 15 250 nA Error Amplifier Section Common Mode Range Vcc = 8V to 40V 0 Open Loop Gain ∆VCOMP = 1V to 4V 80 V IN-2 100 0 75 VIN-2 mV V 100 dB Unity Gain Bandwidth TJ = 25°C, Note 2 0.8 0.8 MHz Output Sink Current VCOMP = 1V 2 2 mA Output Source Current VCOMP = 4V 8 8 mA Current Sense Section Input Bias Current -2.0 -5 -2.0 -5 µA Internal Clamp .425 0.5 .575 .405 0.5 .595 V Divider Gain .180 0.2 .220 .170 0.2 .230 V/V .8 1.0 1.2 .75 1.0 1.25 V 20 22 17 20 23 µs Internal Offset Voltage Timing Section Output Off Time 18 Upper Mono Threshold 5.0 5.0 V Lower Mono Threshold 2.0 2.0 V Decoder Section High-Level Input Voltage 2.2 2.5 V Low-Level Input Voltage 0.8 0.8 V High-Level Input Current 10 10 µA Low-Level Input Current -10 µA -10 Output Section Output Leakage Current VCC = 40V 1500 µA VF1 Schottky Diode IO = 2A 1.5 2.0 1.5 2.0 V VF1 Substrate Diode IO = 2A 2.2 3.0 2.2 3.0 V Total Output Voltage Drop IO = 2A, Note 3 3.0 3.6 3.0 3.6 V 500 2 UC1620 UC3620 ELECTRICAL CHARACTERISTICS: Unless otherwise stated, these specifications apply for TA = 0°C to 70°C for 3620; TA = 55°C to +125°C for UC1620; VCC = 20V, RT = 20V, RT = 10k, CT = -2.2nF. TA=TJ. PARAMETER TEST CONDITIONS UC3620 MIN TYP UC1620 MAX MIN TYP UNIT MAX Output Section (cont.) Output Rise Time RL = 44Ω 150 150 ns Output Fall Time RL = 44Ω 150 150 ns Under Voltage Lockout Startup Threshold 8.0 Threshold Hysteresis 8.0 0.5 0.5 V V Thermal Shutdown Junction Temperature Note 2 150 180 150 180 °C 55 mA Total Standby Current Supply Current 32 55 32 Note 2: These parameters, although guaranteed over the recommended operating conditions, are not 100% tested in production. Note 3: The total voltage drop is defined as the sum of both top and bottom side driver. Hall lines require pull-up resistors. TABLE 1 STEP 1 2 3 4 5 6 1 2 3 4 5 6 FWD/ REV 1 1 1 1 1 1 0 0 0 0 0 0 Ha Hb Hc AOUT BOUT COUT 1 1 1 0 0 0 1 1 1 0 0 0 0 0 1 1 1 0 0 0 1 1 1 0 1 0 0 0 1 1 1 0 0 0 1 1 H H O L L O L L O H H O L O H H O L H O L L O H O L L O H H O H H O L L CURRENT SENSING Referring to Figure 1, emitter current is sensed across RS and fed back through a low pass filter to the current sense pin 7. This filter is required to eliminate false triggering of the monostable due to leading edge current spikes. Actual filter values, although somewhat dependent on external loads, will generally be in the 1kΩ and 1000pF range. TIMING An R-C time constant on pin 9 is used by the monostable to generate a fixed off time at the outputs according to the formula: TOFF = .916RTCT H = HIGH OUTPUT L = LOW OUTPUT O = OPEN OUTPUT As the peak current in the emitters approaches the value at the minus (-) input of the on-board comparator, the monostable is triggered, causing the outputs to be turned CIRCUIT DESCRIPTION The UC3620 is designed for implementation of a complete 3-∅ brushless DC servo drive using a minimum number of external components. Below is a functional description of each major circuit feature. DECODER Table 1 shows the decoding scheme used in the UC3620 to decode and drive each of three high current totem pole output stages. A forward/reverse signal, pin 13, is used to provide direction. At any point in time, one driver is sourcing, one driver is sinking, and the remaining driver is off or tri-stated. Pulse width modulation is accomplished by turning the sink driver off during the monostable reset time, producing a fixed off-time chop mode. Controlled output rise and fall times help reduce electrical switching noise while maintaining relatively small switching losses. Figure 1. Current Sense Filter 3 UC1620 UC3620 CIRCUIT DESCRIPTION (cont.) tive (-) input will limit peak current to a maximum value. A fixed 0.5V internal clamp has been included on the UC3620, and any current spike in the output which generates a sensed voltage greater than 0.5V will immediately shut down the outputs. Actual peak current values may be programmed by selecting the appropriate value of RS according to the formula: off. On time is determined by the amount of time required for motor current to increase to the value required to retrip the monostable. A timing sequence of these events is shown in Figure 2. RS = ICURRENTLIMIT ERROR AMPLIFIER LIMIT A high performance, on-board error amplifier is included to facilitate implementing closed loop motor control. Error voltage generation and loop compensation are easily accomplished by appropriately configuring the gain and feedback of this amplifier. To provide a larger dynamic signal range at the output of the error amplifier, a divide by 5 resistor network is used to reduce the error signal level before applying to the internal comparator. In addition, a one volt offset has been introduced at the output of the error amplifier to guarantee control down to zero current in the output stages. Since this offset is divided by the open loop gain of the feedback loop, it has virtually no effect on closed loop performance. Figure 2. Chopped Mode Timing Diagram CURRENT LIMIT Since peak current is being controlled at all times by the internal comparator, a simple voltage clamp at its negative (-) input will limit peak current to a maximum value. A fixed 0.5V internal clamp has been included on the UC3620, and any current spike in the output which generates a sensed voltage greater than 0.5V will immediately shut down the outputs. Actual peak current values may be programmed by selecting the appropriate value of RS according to the formula: RS = 0.5 PROTECTION FUNCTIONS Protective functions including under-voltage lockout, peak current limiting, and thermal shutdown, provide an extremely rugged device capable of surviving under many types of fault conditions. Under-voltage lockout guarantees the outputs will be off or tri-slated until VCC is sufficient for proper operation of the chip. Current limiting limits the peak current for a stalled or shorted motor, whereas thermal shutdown will tri-state the outputs if a temperature above 150°C is reached. 0.5 ICURRENTLIMIT Since peak current is being controlled at all times by the internal comparator, a simple voltage clamp at its nega- 4 UC1620 UC3620 TYPICAL APPLICATIONS *Both VCC PWR and VCC LOGIC pins must be connected together when using the SP package. 3-∅ Brushless DC Open Loop Motor Drive *Both VCC PWR and VCC LOGIC pins must be connected together when using the SP package. 3-∅ Brushless DC Open Loop Motor with Current Limit at 2A. 5 UC1620 UC3620 *Both VCC PWR and VCC LOGIC pins must be connected together when using the SP package. Closed Loop Speed Control Servo UNITRODE CORPORATION 7 CONTINENTAL BLVD. • MERRIMACK, NH 03054 TEL. (603) 424-2410 • FAX (603) 424-3460 6 PACKAGE OPTION ADDENDUM www.ti.com 30-Mar-2005 PACKAGING INFORMATION Orderable Device Status (1) Package Type Package Drawing Pins Package Eco Plan (2) Qty Lead/Ball Finish MSL Peak Temp (3) UC1620SP OBSOLETE UTR 24 TBD Call TI Call TI UC1620SP883B OBSOLETE UTR 24 TBD Call TI Call TI UC1620SP883C OBSOLETE UTR TBD Call TI Call TI UC3620SP OBSOLETE UTR 24 TBD Call TI Call TI UC3620V OBSOLETE UTR 15 TBD Call TI Call TI UC3620VH OBSOLETE UTR 15 TBD Call TI Call TI (1) The marketing status values are defined as follows: ACTIVE: Product device recommended for new designs. LIFEBUY: TI has announced that the device will be discontinued, and a lifetime-buy period is in effect. NRND: Not recommended for new designs. Device is in production to support existing customers, but TI does not recommend using this part in a new design. PREVIEW: Device has been announced but is not in production. Samples may or may not be available. OBSOLETE: TI has discontinued the production of the device. (2) Eco Plan - The planned eco-friendly classification: Pb-Free (RoHS) or Green (RoHS & no Sb/Br) - please check http://www.ti.com/productcontent for the latest availability information and additional product content details. TBD: The Pb-Free/Green conversion plan has not been defined. Pb-Free (RoHS): TI's terms "Lead-Free" or "Pb-Free" mean semiconductor products that are compatible with the current RoHS requirements for all 6 substances, including the requirement that lead not exceed 0.1% by weight in homogeneous materials. Where designed to be soldered at high temperatures, TI Pb-Free products are suitable for use in specified lead-free processes. Green (RoHS & no Sb/Br): TI defines "Green" to mean Pb-Free (RoHS compatible), and free of Bromine (Br) and Antimony (Sb) based flame retardants (Br or Sb do not exceed 0.1% by weight in homogeneous material) (3) MSL, Peak Temp. -- The Moisture Sensitivity Level rating according to the JEDEC industry standard classifications, and peak solder temperature. Important Information and Disclaimer:The information provided on this page represents TI's knowledge and belief as of the date that it is provided. TI bases its knowledge and belief on information provided by third parties, and makes no representation or warranty as to the accuracy of such information. Efforts are underway to better integrate information from third parties. TI has taken and continues to take reasonable steps to provide representative and accurate information but may not have conducted destructive testing or chemical analysis on incoming materials and chemicals. TI and TI suppliers consider certain information to be proprietary, and thus CAS numbers and other limited information may not be available for release. In no event shall TI's liability arising out of such information exceed the total purchase price of the TI part(s) at issue in this document sold by TI to Customer on an annual basis. Addendum-Page 1 IMPORTANT NOTICE Texas Instruments Incorporated and its subsidiaries (TI) reserve the right to make corrections, modifications, enhancements, improvements, and other changes to its products and services at any time and to discontinue any product or service without notice. Customers should obtain the latest relevant information before placing orders and should verify that such information is current and complete. All products are sold subject to TI’s terms and conditions of sale supplied at the time of order acknowledgment. TI warrants performance of its hardware products to the specifications applicable at the time of sale in accordance with TI’s standard warranty. Testing and other quality control techniques are used to the extent TI deems necessary to support this warranty. Except where mandated by government requirements, testing of all parameters of each product is not necessarily performed. TI assumes no liability for applications assistance or customer product design. Customers are responsible for their products and applications using TI components. To minimize the risks associated with customer products and applications, customers should provide adequate design and operating safeguards. TI does not warrant or represent that any license, either express or implied, is granted under any TI patent right, copyright, mask work right, or other TI intellectual property right relating to any combination, machine, or process in which TI products or services are used. Information published by TI regarding third-party products or services does not constitute a license from TI to use such products or services or a warranty or endorsement thereof. Use of such information may require a license from a third party under the patents or other intellectual property of the third party, or a license from TI under the patents or other intellectual property of TI. Reproduction of information in TI data books or data sheets is permissible only if reproduction is without alteration and is accompanied by all associated warranties, conditions, limitations, and notices. Reproduction of this information with alteration is an unfair and deceptive business practice. TI is not responsible or liable for such altered documentation. Resale of TI products or services with statements different from or beyond the parameters stated by TI for that product or service voids all express and any implied warranties for the associated TI product or service and is an unfair and deceptive business practice. TI is not responsible or liable for any such statements. Following are URLs where you can obtain information on other Texas Instruments products and application solutions: Products Applications Amplifiers amplifier.ti.com Audio www.ti.com/audio Data Converters dataconverter.ti.com Automotive www.ti.com/automotive DSP dsp.ti.com Broadband www.ti.com/broadband Interface interface.ti.com Digital Control www.ti.com/digitalcontrol Logic logic.ti.com Military www.ti.com/military Power Mgmt power.ti.com Optical Networking www.ti.com/opticalnetwork Microcontrollers microcontroller.ti.com Security www.ti.com/security Telephony www.ti.com/telephony Video & Imaging www.ti.com/video Wireless www.ti.com/wireless Mailing Address: Texas Instruments Post Office Box 655303 Dallas, Texas 75265 Copyright 2005, Texas Instruments Incorporated