STK554U3xx series Application Note www.onsemi.com 1. Product synopsis This application handbook is intended to provide practical guidelines for the STK554U3xx series use. The STK554U3xx series is Intelligent Power Module (IPM) based upon ONs Insulated Metal Substrate Technology (IMST) for 3-phase motor drives which contain the main power circuitry and the supporting control circuitry. The key functions are outlined below: Highly integrated device containing all High Voltage (HV) control from HV-DC to 3-phase outputs in a single small SIP module. Output stage uses IGBT/FRD technology and implements Under Voltage Protection (UVP) and Over Current Protection (OCP) with a Fault Detection output flag. Internal Boost diodes are provided for high side gate boost drive. Option of a combined or individual shunt resistor per phase for OCP. Externally accessible embedded thermistor for substrate temperature measurement. All control inputs and status outputs are at low voltage levels directly compatible with microcontrollers. Single control power supply due to internal bootstrap circuit for high side pre-driver circuit. Mounting points are available on SIP package A simplified block diagram of a motor control system is shown if Figure 1. Intelligent Power Module Figure 1. Motor Control System Block Diagram Semiconductor Components Industries, LLC, 2014 Nov, 2014 1/23 Rev.3 STK554U3xx series Application Note 2. Product description Table1. gives an overview of the available devices, for a detailed description of the packages refer to Chapter 6. Device Feature Package Voltage (VCEmax.) Current (Ic) Peak current (Ic) Isolation voltage Shunt resistance STK554U362A-E 10A 20A STK554U392A-E STK554U3A2A-E triple shunts SIP1A – horizontal pins 600V 15A 20A 30A 40A 2000V external Vertical type models; STK554U3xxC-E series are available for pin forming option. Table 1. Device Overview VB3( 1) W,VS3( 2) VB2( 5) V,VS2( 6) VB1( 9) U,VS1(10) V+ (13) DB DB DB U.V. U.V. U.V. U- (17) V- (19) W- (21) Level Level Level Shifter Shifter Shifter HIN1(20) HIN2(22) HIN3(23) Logic Logic Logic LIN1(24) LIN2(25) LIN3(26) Thermistor TH(27) ITRIP(16) Shutdown VDD(28) VSS(29) Enable/Disable Under voltage + Detect - S Timer Q R Vref Latch time about 2ms FLTEN(18) Figure 2. STK554U3xx series equivalent circuits The high side drive is used with a bootstrap circuit to generate the higher voltage needed for gate drive. The Boost diodes are internal to the part and sourced from VDD (15V). There is an internal level shift circuit for the high side drive signals allowing all control signals to be driven directly from Vss levels common with the control circuit such as the microcontroller without requiring external level shift such as opto isolators. 2/23 STK554U3xx series Application Note 3. Performance test guidelines The following Chapter gives performance test method shown in Figures 3 to 7. 3.1. Switching time definition and performance test method trr 10% 90% VCE 90% 10% Io td(ON) 10% td(OFF) tr tf tOFF tON IN Figure 3. Switching time definition Ex) Lower side U phase measurement + VB1 VD1=15V VS1,U VB2 VD2=15V VS2,V VS1,U Vcc VB3 CS VD3=15V VS3,W VDD Io VD4=15V Input signal U- LIN1 VSS ITRIP Figure 4. Evaluation circuit (Inductive load) IPM Ho HIN1,2,3 CS VCC Driver U,V,W LIN1,2,3 Lo Input signal Io Input signal Io Figure 5. Switching loss circuit 3/23 STK554U3xx series Application Note IPM Ho HIN1,2,3 CS VCC Driver U,V,W LIN1,2,3 Lo Input signal Io Input signal Io Figure 6. R.B.SOA circuit IPM Ho HIN1,2,3 CS VCC Driver U,V,W LIN1,2,3 Lo Input signal Io Input signal Io Figure 7. S.C.SOA circuit 4/23 STK554U3xx series Application Note 3.2. Thermistor Characteristics An integrated thermistor is used to sense the internal module temperature its electrical characteristic is outlined below. Parameter Resistance Resistance B-Constant(25-50°C) Symbol R25 Condition Tc=25°C R125 Tc=125°C Min 44.6 B Temperature Range Typ. 47.0 Max 49.4 Unit kΩ 1.28 1.41 1.53 kΩ 4010 4050 4091 K °C -40 +125 Table 2. NTC Thermistor value R25 is the value of the integrated NTC thermistor at Tc=25 °C. The resistance value is 100kΩ±5% and the value of the B-Constant (25-50°C) is 4050K±1%. The temperature depended value is calculated as shown in the formula. 𝐑(𝐭) = 𝐑 𝟐𝟓 × 𝟏 𝟏 𝐁(𝐓−𝟐𝟗𝟖) 𝐞 The resulting in the NTC values over temperatures Case Temperature(Tc) - Thermal resistance(RTH) Thermistor Resistanse, RTH-Kohm 10000 min typ max 1000 100 10 1 -40 -30 -20 -10 0 10 20 30 40 50 60 70 80 90 100 110 120 130 Case temperature, Tc-degC Figure 8. typical NTC value over temperature 4. Protective functions and Operation Sequence This chapter describes the protection features. over current protection short circuit protection under Voltage Lockout (UVLO) protection cross conduction prevention 5/23 STK554U3xx series Application Note 4.1. Over current protection In difference to the internal single shunt series modules the STK554Uxxx series modules utilize an external shunt resistor for the OCP functionality. As shown in Figure 9 the emitters of all three lower side IGBTs brought out to module pins. An external “over current protection circuitry” consisting of the shunt resistor and an RC filter network define the trip level. IPM V+ VSS ITRIP Driver U V W VShunt Over current protection circuit UVW- Figure 9. Over-current protection circuit setting The OCP function is implemented by comparing the voltage on the Itrip input to an internal reference of 0.49V (typ). In case the voltage on this terminal i.e. across the shunt resistor exceeds the trip level an OCP fault is triggered. Note: The current value of the OCP needs to be set by correctly sizing the external shunt resistor to less than 2x of the modules rated current. In case of an OCP event all internal gate drive signal for the IGBTs of all three phases become inactive and the FLT/EN fault signal output is activated (low). An RC filter is used on the Itrip input to prevent an erroneous OCP detection due to normal switching noise and/or recovery diode current. The time constant of that RC filter should be set to a value between 1.5μ to 2μs. In any case the time constant must be shorter than the IGBTs short current safe operating area (SCSOA) according to Figure 10. The resulting OCP level due to the filter time constant is shown in Figure 11. Figure 10. IGBT SCSOA 6/23 Collector Current Ic (A) STK554U3xx series Application Note Over-current protective level Collector Current Waveform Input pulse width tw (usec.) Figure 11. filter time constant For optimal performance all traces around the shunt resistor need to be kept as short as possible Figure 12 shows the sequence of events in case of an OCP event. HIN/LIN Protection state Set Reset HVG/LVG Normal operation Over current detection Over current IGBT turn off Output Current Ic (A) Over current reference voltage Voltage of Shunt resistor RC circuit time constant Fault output Fault output Figure 12. Over current protection Timing chart 7/23 STK554U3xx series Application Note 4.2. Under Voltage Lockout Protection The UVLO protection is designed to prevent unexpected operating behavior as described in Table 3. Both High-side and Low-side have UV protecting function. However the fault signal output only corresponds to the Low-side UVLO Protection. During the UVLO state the fault output is continuously driven (low). VDD Voltage (typ. Value) Operation behavior < 12.5V As the voltage is lower than the UVLO threshold the control circuit is not fully turned on. A perfect functionality cannot be guaranteed. 12.5 V – 13.5 V IGBTs can work, however conduction and switching losses increase due to low voltage gate signal. 13.5 V – 16.5 V Recommended conditions 16.5 V – 20.0 V IGBTs can work. Switching speed is faster and saturation current higher, increasing short-circuit broken risk. > 20.0 V Control circuit is destroyed. Absolute max. rating is 20 V. Table 3. Module operation according to control supply voltage The sequence of events in case of a low side UVLO event (IGBTs turned off and active fault output) is shown in Figure 13. Figure 14 shows the same for a high side UVLO (IGBTs turned off and no fault output). LIN Protection state Reset Set Reset Control supply voltage VD Under voltage reset Under voltage trip Normal operation Output Current Ic (A) After the voltage level reaches UV reset, the circuits start to operate when next input is applied . IGBT turn off Fault output Fault output Figure 13. Low side UVLO timing chart 8/23 STK554U3xx series Application Note HIN Reset Protection state Set Reset Control supply voltage VD Under voltage reset Under voltage trip Normal operation Output Current Ic (A) After the voltage level reaches UV reset, the circuits start to operate when next input is applied . IGBT turn off Fault output Keeping high level output ( No Fault output ) Figure 14. High side UVLO timing chart 4.3. Cross conduction prevention The STK554U3xx series module implement a cross conduction prevention logic at the pre-driver to avoid simultaneous drive of the low- and high-side IGBTs as shown in Figure 15. Figure 15. Cross Input Conduction Prevention In case of both high and low side drive inputs are active (high) the logic prevents both gates from being driven – a corresponding timing diagram can be found in Figure 16 below. 9/23 STK554U3xx series Application Note HIN LIN Shoot-Through Prevention HVG Normal operation Normal operation LVG VDD Fault output Keeping high level output ( No Fault output ) Figure 16. cross conduction prevention timing diagram Even so cross conduction on the IGBTs due to incorrect external driving signals is prevented by the circuitry the driving signals (HIN and LIN) need to include a “dead time”. This period where both inputs are inactive between either one becoming active is required due to the internal delays within the IGBTs. Figure 17 shows the delay from the HIN-input via the internal HVG to high side IGBT, the similar path for the low side and the resulting minimum dead time which is equal to the potential shoot through period: HIN LIN tON High Side IGBT Low Side IGBT tOFF Shoot-Trough Period Dead time = tOFF-tON Figure 17. Shoot Trough Period 10/23 STK554U3xx series Application Note 5. PCB design and mounting guidelines This chapter provides guidelines for an optimized design and PCB layout as well as module mounting recommendations to appropriately handle and assemble the IPM. 5.1. Application (schematic) design The following two figures 18 gives an overview of the external circuitry’s functionality when designing with the STK554U3xx series module. Figure 18. STK554U3xx series application circuit Figure 19. PCB design reference 11/23 STK554U3xx series Application Note 5.2. Pin by pin design and usage notes This section provides pin by pin PCB layout recommendations and usage notes. For a complete list of module pins refer to the datasheet or Chapter 6. +, U-, V-, W- These pins are connected with the main DC power supply. The applied voltage is up to the Vcc level. Overvoltage on these pins could be generated by voltage spikes during switching at the floating inductance of the wiring. To avoid this behavior the wire traces need to be as short as possible to reduce the floating inductance. In addition a snubber capacitor needs to be placed as close as possible to these pins to stabilize the voltage and absorb voltage surges. U, V, W These terminals are the output pins for connecting the 3-phase motor. They share the same GND potential with each of the high side control power supplies. Therefore they are also used to connect the GND of the bootstrap capacitors. These bootstrap capacitors should be placed as close to the module as possible. VDD, VSS These pins connect with the circuitry of the internal protection and pre-drivers for the low-side power elements and also with the control power supply of the logic circuitry. Voltage to input these terminals is monitored by the under voltage protection circuit. The VSS terminal is the reference voltage for the control inputs signals. VB1, VB2, VB3 The VBx pins are internally connected to the positive supply of the high-side drivers. The supply needs to be floating and electrically isolated. The boot-strap circuit shown in Figure 20 forms this power supply individually for every phase. Due to integrated boot resistor and diode (RB & DB) only an external boot capacitor (CB) is required. CB is charged when the following two conditions are met. ① Low-side signal is input ② Motor terminal voltage is low level The capacitor is discharged while the high-side driver is activated. Thus CB needs to be selected taking the maximum on time of the high side and the switching frequency into account. DB CB Driver RB VDD Driver Figure 20. Boot Strap Circuit 12/23 STK554U3xx series Application Note The voltages on the high side drivers are individually monitored by the under voltage protection circuit. In case an UVP event is detected on a phase its operation is stopped. Typically a CB value of less or equal 47uF (±20%) is used. In case the CB value needs to be higher an external resistor (of apx. 20Ω or less) should be used in series with the capacitor to avoid high currents which can cause malfunction of the IPM. HIN1, LIN1, HIN2, LIN2, HIN3, LIN3 These pins are the control inputs for the power stages. The inputs on HIN1/HIN2/HIN3 control the high-side transistors of U/V/W, and the inputs on LIN1/LIN2/LIN3 control the low-side transistors of U/V/W respectively. The input are active high and the input thresholds VIH and VIL are 5V compatible to allow direct control with a microcontroller system Simultaneous activation of both low and high side is prevented internally to avoid shoot through at the power stage. However, due to IGBT switching delays the control signals must include a dead-time. The equivalent input stage circuit is shown in Figure 21. IN 33k VSS Figure 21. Internal Input Circuit For fail safe operation the control inputs are internally tied to VSS via a 33kΩ (typ) resistor. To avoid switching captured by external wiring to influence the module behavior an additional external low-ohmic pull-down resistor with a value of 2.2kΩ-3.3kΩ should be used. FLTEN The output might not respond when the width of the input pulse is less than 1µs (both ON and OFF). The FLTEN pin is an active low input and open-drain output. It is used to indicate an internal fault condition of the module and also can be used to disable the module operation. The I/O structure is shown in Figure 22. The internal sink current IoSD during an active fault is nominal 2mA @ 0.1V. Depending on the interface supply voltage the external pull-up resistor (RP) needs to be selected to set the low voltage below the VIL trip level. For the commonly used supplies VP: VP = 15V -> RP >= 20kΩ VP = 5V -> RP>= 6.8kΩ 13/23 STK554U3xx series Application Note VP VDD RP FLTEN VSS Figure 22. Fault Connection For a detailed description of the fault operation refer to Chapter 4. Note: The Fault signal does not latch permanently. After the protection event ended and the fault clear time(2ms) passed, the module operation is automatically re-started. Therefore the input needs to be driven low externally activated as soon as a fault is detected. TH An internal thermistor to sense the substrate temperature is connected between TH and VSS. By connecting an external pull-up resistor to arbitrary voltage, the module temperature can be monitored. Please refer to heading 3.2 for details of the thermistor. Note: This is the only means to monitor the substrate temperature indirectly. 5.3. Heat sink mounting and torque If a heat sink is used, insufficiently secure or inappropriate mounting can lead to a failure of the heat sink to dissipate heat adequately. This can lead to an inability of the device to provide its inherent performance, a serious reduction in reliability, or even destruction, burst and burn of the device due to overheating. The following general points should be observed when mounting IPM on a heat sink: 1. Verify the following points related to the heat sink: - There must be no burrs on aluminum or copper heat sinks. - Screw holes must be countersunk. - There must be no unevenness in the heat sink surface that contacts IPM. - There must be no contamination on the heat sink surface that contacts IPM. 2. Highly thermal conductive silicone grease needs to be applied to the whole back (aluminum substrate side) uniformly, and mount IPM on a heat sink. Upon re-mounting apply silicone grease(100um to 200um) again uniformly. 3. For an intimate contact between the IPM and the heat sink, the mounting screws should be tightened gradually and sequentially while a left/right balance in pressure is maintained. Either a bind head screw or a truss head screw is recommended. Please do not use tapping screw. We recommend using a flat washer in order to prevent slack. 14/23 STK554U3xx series Application Note The standard heat sink mounting condition of STK554U3xx series is as follows. Table 4. heat sink mounting Steps to mount an IPM on a heat sink 1st: Temporarily tighten maintaining a left/right balance. 2nd : Finally tighten maintaining a left/right balance. 15/23 STK554U3xx series Application Note 5.4. Mounting and PCB considerations In designs in which the printed circuit board and the heat sink are mounted to the chassis independently, use a mechanical design which avoids a gap between IPM and the heat sink, or which avoids stress to the lead frame of IPM by an assembly that a moving IPM is forcibly fixed to the heat sink with a screw. IPM Figure 23. Fix to Heat Sink Maintain a separation distance of at least 1.5 mm between the IPM case and the printed circuit board. In particular, avoid mounting techniques in which the IPM substrate or case directly contacts the printed circuit board. Do not mount IPM with a tilted orientation. This can result in stress being applied to the lead frame and IPM substrate could short out tracks on the printed circuit board. Always mount the IPM vertically. If stress is given by compulsory correction of a lead frame after the mounting, a lead frame may drop out. Be careful of this point. IPM When designing the PCB layout take care that the bent part portion of the lead frame pins does not short-circuit to VIA holes or tracks on the PCB. IPM 16/23 STK554U3xx series Application Note Since the use of sockets to mount IPM can result in poor contact with IPM leads, we strongly recommend making direct connections to PCB. IPMs are flame retardant. However, under certain conditions, it may burn, and poisonous gas may be generated or it may explode. Therefore, the mounting structure of the IPM should also be flame retardant. Mounting on a Printed Circuit Board 1. Align the lead frame with the holes in the printed circuit board and do not use excessive force when inserting the pins into the printed circuit board. To avoid bending the lead frames, do not try to force pins into the printed circuit board unreasonably. 2. Do not insert IPM into printed circuit board with an incorrect orientation, i.e. be sure to prevent reverse insertion. IPM may be destroyed, exploded, burned or suffer a reduction in their operating lifetime by this mistake. 3. Do not bend the lead frame. 5.5. Cleaning IPM has a structure that is unable to withstand cleaning. As a basic policy, do not clean independent IPM or printed circuit boards on which an IPM is mounted. 6. Package Outline STK554U3xx series is SIP1A package. (Single-inline-package) Every second pin is bent forward to form two rows on the PCB see Figure 24. 6.1. Package outline and dimension STK554U3xxA-E (Horizontal type) 17/23 STK554U3xx series Application Note STK554U3xxC-E (Vertical type) Figure 24. STK554U3xx series Package Outline 3.21mm TYP 3.01mm MIN 0.67mm TYP 1.27mm TYP 0.47mm MIN +0.1 6.7 -0.5 mm Figure 25. Pin to Pin Detail 18/23 STK554U3xx series Application Note 6.2. Laser Marking Figure 26. Laser marking detail Note 1: The labeling designates the model number – centered within a field of 4 mm width and 30 mm length Note2: The labeling designates the order number – right justified within a field of 2.5 and 14 mm length mm width *We examine the design except for the above. 19/23 STK554U3xx series Application Note 6.3. Pin Out Description Pin 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 Name VB3 W,VS3 NA NA VB2 V,VS2 NA NA VB1 U,VS1 NA NA + NA NA ITRIP UFLTEN VHIN1 WHIN2 HIN3 LIN1 LIN2 LIN3 TH VDD VSS Description High Side Floating Supply Voltage 3 Output 3 - High Side Floating Supply Offset Voltage none none High Side Floating Supply voltage 2 Output 2 - High Side Floating Supply Offset Voltage none none High Side Floating Supply voltage 1 Output 1 - High Side Floating Supply Offset Voltage none none Positive Bus Input Voltage none none Shut-down Pin Low Side Emitter Connection - Phase 1 Fault Signal Output & Enable Low Side Emitter Connection - Phase 2 Logic Input High Side Gate Driver - Phase 1 Low Side Emitter Connection - Phase 3 Logic Input High Side Gate Driver - Phase 2 Logic Input High Side Gate Driver - Phase 3 Logic Input Low Side Gate Driver - Phase 1 Logic Input Low Side Gate Driver - Phase 2 Logic Input Low Side Gate Driver - Phase 3 Temperature Monitor +15V Control Power Supply Negative Control Power Supply 20/23 STK554U3xx series Application Note 7. Demo Board The demo board consists of the minimum required components such as snubber capacitor and bootstrap circuit elements of STK554U3xx series. Evaluation Board + - VSS 220uF/35V + 0.1uF TH VDD LIN3 LIN2 LIN1 HIN3 W- ITRIP HIN2 VS1, U V- VB2 + HIN1 16 17 18 19 20 21 22 23 24 25 26 27 28 29 U- 13 FLTEN 9 10 VB1 6 VS2, V VB3 5 + - 2 + - 1 VS3, W STK554U3xx series 47uF/50V×3 0.1uF×3 10kΩ VSS Vext 10kΩ U VDD U- V V- W WTH ITRIP + 470uF/450V×2 - + - + - 1kΩ FLTEN 2.2uF/630V Shunt resistor LIN3 LIN2 LIN1 HIN3 HIN2 HIN1 3.3kΩ×6 100pF×6 100Ω×6 Figure 27. Evaluation board schematic Length : 96mm Side : 128mm Thickness : 1.6mm Rigid double-sided substrate (Material : FR-4) Both sides resist coating Copper foil thickness : 70um Figure 28. Evaluation board picture 21/23 STK554U3xx series Application Note Surface Back side Figure 29. Evaluation board PCB layout (TOP view) The heat sink of this example is assumed operation at 10A. Heat sink thermal resistance : 2.0deg./W Notes : There is no holes for installing the heat sink in this board. Therefore, first of all, it is necessary to install the heat sink to the IPM. Then, please implement the IPM to the board. Figure 30. Installation example of the heat sink Red line frame : Connector For the connection to the control part STK554U3xx series W V VSS U VDD U- 1kΩ V- 10kΩ W- Blue line frame : Test pins For monitoring each control signal Purple line frame : Low pass filter and pulldown resistor for control terminal Low pass filter is composed of resistor of 100Ω, and capacitor of 100pF. Vext 10kΩ TH ITRIP FLTEN LIN3 LIN2 LIN1 HIN3 HIN2 HIN1 100Ω 100pF 3.3kΩ Vext VSS VDD UVWTH ITRIP FLTEN LIN3 LIN2 LIN1 HIN3 HIN2 HIN1 VSS NC NC NC NC Vext terminal is connected pull-up resistor for TH and Fault pins. Please impress arbitrary voltage to this terminal. Brown line frame : Pull-up resistor for FLTEN and TH Pull-down resistor for ITRIP ITRIP pull-down 1kΩ - + TH pull-up 10kΩ FLTEN pull-up 10kΩ Evaluation Board Green line frame : U, V, W terminal Please connect to the motor. Orange line frame : +, - terminal Please connect to DC power supply. Figure 31. Description of each pin 22/23 STK554U3xx series Application Note STK554U3xx series W Motor V U VSS Logic Vext VDD U- 1kΩ V- 10kΩ W- 10kΩ TH ITRIP FLTEN LIN3 LIN2 LIN1 HIN3 HIN2 HIN1 - 100Ω 100pF 3.3kΩ DC 15V Vext VSS VDD UVWTH ITRIP FLTEN LIN3 LIN2 LIN1 HIN3 HIN2 HIN1 VSS NC NC NC NC + DC power supply Evaluation Board Figure 32. Evaluation board instructions Operation procedure Step1: Please connect IPM, each power supply, logic parts, and the motor to the evaluation board, and confirm that each power supply is OFF at this time. Step2: Please impress the power supply of DC15V. Step3: Please perform a voltage setup according to specifications, and impress the power supply between the "+" and the "-" terminal. Step4: By inputting signal to the logic part, IPM control is started. (Therefore, please set electric charge to the boot-strap capacitor of upper side to turn on lower side IGBT before running.) * When turning off the power supply part and the logic part, please carry out in the reverse order to above steps. ON Semiconductor and the ON logo are registered trademarks of Semiconductor Components Industries, LLC (SCILLC) or its subsidiariesin the United States and/or other countries. SCILLC owns the rights to a number of patents, trademarks, copyrights, trade secrets, and other intellectual property. A listing of SCILLC’s product/patent coverage may be accessed at www.onsemi.com/site/pdf/Patent-Marking.pdf . SCILLC reserves the right to make changes without further notice to any products herein. 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