AN98057 1010 Octal Side Driver (OLSD) Application Note AN980

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AN98057 1010 Octal Side Driver (OLSD) Application Note AN980

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1010 Octal Side Driver (OLSD)
AN98057
1010 Octal Side Driver (OLSD)
Application Note AN98057
Abstract
Octal Side Driver TJA1010 smart power device, dedicated controlling eight relays. designed operate under harsh environmental conditions automotive system. example, handles wide voltage range, that occur supply network output stages fully protected. TJA1010 controlled microcontroller serial peripheral interface (SPI). also full diagnostic information from load outputs delivered. Further features status outputs, low-power mode, power-on reset, over- undervoltage shutdown. This application note gives information implementation TJA1010 into electronic control unit, focusing requirements automotive systems.
Philips Electronics N.V. 1998 rights reserved. Reproduction whole part prohibited without prior written consent copyright owner. information presented this document does form part quotation contract, believed accurate reliable changed without notice. liability will accepted publisher consequence use. Publication thereof does convey imply license under patent- other industrial intellectual property rights.
1010 Octal Side Driver (OLSD)
Application Note AN98057
1010 Octal Side Driver (OLSD)
AN98057
Author: Thomas Stork Systems Laboratory Hamburg, Germany
Keywords Automotive, Smart Power, Thermal Management, Relays, Supply Interface, 7637 Serial Peripheral Interface (SPI)
Date: 25th March 1998
1010 Octal Side Driver (OLSD)
Application Note AN98057
Summary This application note intended provide application support designing TJA1010 into electronic control units, especially automotive systems. paper discusses interface device loads, microcontroller supply. Therefore, characteristics features output stages described, including thermal model. device behaviour under typical supply network conditions vehicle covered. Furthermore, control diagnostics with microcontroller described detail.
1010 Octal Side Driver (OLSD) CONTENTS
Application Note AN98057
INTRODUCTION FEATURES OUTPUT STAGES
DMOS Power Switches 3.1.1 General Characteristics 3.1.2 Maximum Load Current Thermal Management Protection Features 3.2.1 Overvoltage Clamp 3.2.2 Short Circuit Overload Protection Driving Relays
SUPPLY INTERFACE.
Behaviour under Typical Supply Conditions Supply Transients (ISO 7637) Clamped Load Dump
SERIAL PERIPHERAL INTERFACE (SPI)
Data Transfer between TJA1010 Microcontroller Controlling TJA1010 with Microcontroller. Cascading OLSDs (Daisy Chain)
DIAGNOSTICS
Diagnostic Functions TJA1010 Diagnostics with TJA1010 Microcontroller
MISCELLANEOUS
Low-Power Mode Reset
REFERENCE
1010 Octal Side Driver (OLSD) List Figures
Fig. Fig. Fig. Fig. Fig. Fig. Fig. Fig. Fig. Fig. Fig. Fig. Fig. Fig. Implementation Octal Side Driver into automotive Simplified block diagram Block diagram with detailed view output stage Thermal equivalent circuit Turn-off inductor External protection supply Connecting TJA1010 microcontroller signals during byte transfer Flow chart data transfer. Daisy Chain OLSDs control signals daisy chain with OLSDs Diagnostic functions Diagnostics using status outputs Diagnostic routine.
Application Note AN98057
List Tables
Table Table Table Table Table Table Table functions Thermal parameters their electrical analogies Thermal equations TJA1010 behaviour versus supply conditions TJA1010 behaviour with supply line transients (protection circuit figure connected) pins TJA1010 Diagnostic truth table
1010 Octal Side Driver (OLSD)
INTRODUCTION
Application Note AN98057
Octal Side Driver TJA1010 contains eight DMOS switches, which dedicated drive relays car. Figure shows, TJA1010 typically implemented into electronic control unit (ECU). switches side configuration. Thus they switch load terminal ground, while other load terminal permanently connected supply. Control switches performed microcontroller serial interface (Serial Peripheral Interface SPI). Besides pure switching function, TJA1010 also provides diagnostic functions: Faults load outputs (open load short circuit load) detected signalled means status outputs. Furthermore, fault information read microcontroller SPI, which allows localize fault. TJA1010 designed withstand harsh conditions automotive system. This covered wide temperature supply voltage ranges well protection features. VBatt
Regulator
OUT1 Microcontroller STATUS outputs Stand-by input OLSD 1010 OUT2 OUT3 OUT4 OUT5 OUT6 OUT7 OUT8 Fig. Implementation Octal Side Driver into automotive
intention this Application Note together with data sheet device provide information, which designer needs successful implementation TJA1010 into ECU.
1010 Octal Side Driver (OLSD)
FEATURES
Application Note AN98057
Figure shows simplified block diagram TJA1010.
STBY
Supply
Output Stage Control, Protection, Monitoring Out1 Out2
shift register
Latch
Status Status Status Outputs
Out7 Out8
Fig. Simplified block diagram
overall circuit subdivided into four blocks. These blocks their features listed below: Output stages Independent DMOS side drivers Over voltage clamping Protection against short circuit load overload Load dump protection Wide operating voltage range, allowing direct supply from line Low-power mode minimum current consumption Undervoltage shutdown power-on reset Control output stages writing data into internal shift register (SPI) Channel selective diagnostic information available reading data from internal shift register Serial output (SO) allows cascading several OLSDs Indication short circuit load (STATSC) open load (STATOL) output stage.
Supply interface
Serial Peripheral Interface (SPI)
Status outputs
1010 Octal Side Driver (OLSD)
Table summarizes functions TJA1010: OUT1.8 STBY STATSC STATOL Function Supply Ground Load outputs Stand-by input Serial input Serial output Serial clock Serial input enable Status output, short circuit Status output, open load Table functions
Application Note AN98057
OUTPUT STAGES
block diagram fig. shows detailed view output stage TJA1010. output stages controlled interface. power switches realized DMOS transistors. Each stage contains circuits driving protection DMOS. Also circuit detecting short circuit open load faults output included here. signals derived this detector partly used within output stage short circuit protection. Besides that, signals from here status outputs diagnostic purposes, described section 6.1.
Temperature Protection
Output Stage Out1 Out2
Supply
current limiting driver shift register
detector logic Latch
Out7 Out8
Status Outputs
Vref
Fig. Block diagram with detailed view output stage
1010 Octal Side Driver (OLSD)
3.1.1 DMOS Power Switches General Characteristics
Application Note AN98057
output drivers TJA1010 DMOS (double diffused MOS) transistors with on-state resistance max. under normal supply conditions car. DMOS technology been chosen because typical advantages over bipolar transistors: Almost zero power dissipation gate drive second breakdown, thus higher ruggedness case overvoltage Paralleling output transistors possible with thermal longtime stability.
3.1.2
Maximum Load Current Thermal Management
Each output TJA1010 operated with continuous current max. junction temperature does exceed junction temperature even held below max. continuous output current Above current limiting becomes active. thermal model fig. supports calculation junction temperature output transistors: TJA1010 comes "medium power" package with GND-pins (pins 20.23), which part leadframe. Thus, thermal paths fig. lead from junctions DMOS outputs accumulation chip these GND-pins from there ambient. This gives significantly lower thermal resistance standard packages, where heat mainly radiated from plastic package ambient. thermal resistance from GND-pins ambient determined board, which device mounted. value given here valid simplest board with minimum footprint. reduced e.g. using order improve heat radiation from board ambient. order reduces thermal resistance 10.15 K/W.
PD,1.8 Rth(j-ac)1.8 Accumulation Solder Point (GND-pins Point Tj,1.8 Junctions DMOS outputs Rth(ac-sp) Rth(sp-amb) Tamb
Ambient
FR-4 board with minimum footprint
Fig. Thermal equivalent circuit
1010 Octal Side Driver (OLSD)
Application Note AN98057
Table summarizes description, values electrical analogies thermal parameters figure Parameter figure PD,1.8 Tj,1.8 Tamb Rth(j-ac),1.8 Description Power dissipation output Junction temperature output Solder point temperature (GND-pins 20.23) Ambient temperature Thermal resistance from junction output "heat accumulation point" Thermal resistance from "heat accumulation point" solder point Ground pins (pins 6.9, 20.23) Thermal resistance from solder point ambient Application dependant Value table table max. continuous operation Electrical analogy Current
Potential, i.e. analog voltage
Rth(ac-sp)
K/W, dependent board
Resistance
Rth(sp-amb)
Table Thermal parameters their electrical analogies Table gives equations power dissipation, junction temperature maximum permissible output currents, based thermal model fig. Equation derived using electrical equivalents table applying law. Equations (3), give permissible dissipation output current respectively, derived from (2), junction temperature should exceed value Tj(max). continuous output current should exceed values stated below (4), even yields higher value. equations given here valid equal dissipation outputs. Fig. however allows derive equations also other load condition. Quantity Dissipation output Output junction temperature Maximum permissible dissipation output Equation equal dissipation outputs
Iout(max) Minimum
Maximum permissible current output
Tj(max) Tj(max) Table Thermal equations
1010 Octal Side Driver (OLSD)
Calculation Example
Application Note AN98057
maximum permissible current output stage calculated, TJA1010 mounted FR-4 board with minimum footprint. outputs connected identical load. maximum ambient temperature Equation yields maximum current OLSD will oper3 ated temperature rating Thus each output operated current rating According equation (1), power dissipation output then leading permissible total power dissipation
3.2.1
Protection Features Overvoltage Clamp
TJA1010 protected against overvoltage pulses output pins means clamp circuits, shown figure zener diode between drain gate each output transistor will turn that transistor partially output voltage exceeds level this means, output voltage clamped level typically This below breakdown voltage DMOS drivers other parts within TJA1010, which connected output pins. automotive applications, there possible sources overvoltage output pins, that could activate output clamps: Positive voltage transients supply line, according 7637 (see section 4.2) Turn-off inductive load without freewheel diode (see section 3.3)
3.2.2
Short Circuit Overload Protection
OLSD protected against short circuit load overload combination current limiting 2-stage over temperature protection: output current TJA1010 limited max. this means, power dissipation thus rate temperature rise device limited. chip temperature exceeds "overtemperature control" threshold typically first stage temperature protection turns those outputs, where short circuit condition been detected, i.e. where output voltage above reference Vref max. (see fig. Overload "soft short circuit" conditions could exist, which raise output voltage above Vref. Outputs operating under such conditions would turned first stage temperature protection. such overloads would cause chip temperature exceed "emergency temperature shutdown" threshold typically second temperature protection stage will turn outputs OLSD. both temperature protection stages, respective outputs turned only duration over temperature condition. They turn again automatically, chip temperature fallen below overtemperature control threshold. Although over temperature protection prevents device failure short circuit overload, operating device such high temperatures over long time will reduce reliability. Thus recommended, turn those outputs permanently off, where short circuit overload been detected (see section
1010 Octal Side Driver (OLSD)
Driving Relays
Application Note AN98057
TJA1010 suitable driving inductive loads like relay coils. turn-off, inductive energy stored coil removed. This principally done freewheel diode across coil. TJA1010 however allows save this extra component, DMOS output transistors clamped. Figure shows typical waveforms output voltage output current TJA1010, when turning inductor without freewheel diode. kickback voltage load output, generated inductive coil energy, clamped TJA1010 safe value typically
Vout
Iout
time Fig. Turn-off inductor
During clamping, power dissipation thus rise junction temperature occurs OLSD outputs. waveform maximum current time during inductive turn-off given datasheet ([1], fig. acutal Iout time during clamping does significantly exceed this waveform, junction temperature will stay within safe limits. This valid, even junction temperature turn-off rating eight outputs turned simultaneously. maximum current waveform data sheet gives safe limit, that stated after tests carried far. results further tests allow extend that limit, permitting clamping higher coil currents and/or longer time. Information this subject will available request.
1010 Octal Side Driver (OLSD)
SUPPLY INTERFACE Behaviour under Typical Supply Conditions
Application Note AN98057
TJA1010 designed handle wide voltage range, that occur supply network car. Table summarizes typical voltage levels supply system respective behaviour TJA1010. Typical Voltage Range Supply Condition Positive transients (ISO 7637) Clamped load dump Jump start regulator degraded Normal Starting phase regulator degraded Starting phase (diesel) Negative transients (ISO 7637), reverse battery Undervoltage shutdown, i.e. supply circuit shuts down output stages below External blocking diode required, section 4.2. Normal operation TJA1010 Behaviour External protection required Pin; Outputs internally clamped energy rating considered. Shutdown output stages above where Vout Vref, section 4.2.
10.5 10.5
Table TJA1010 behaviour versus supply conditions
Supply Transients (ISO 7637) Clamped Load Dump
Figure shows circuit protecting TJA1010 against positive negative transients supply line. According table TJA1010 requires external protection supply against positive voltages against negative voltages. This provided respectively. also serves reverse battery protection required most ECUs anyway order protect 5V-regulator, indicated figure function supply OLSD other components connected VBatt during negative transients, where blocking. should provide impedance transients with high dV/dt.
Regulator
VBatt
OLSD TJA1010
Load
Fig. External protection supply
1010 Octal Side Driver (OLSD)
Application Note AN98057
Table summarizes TJA1010 behaviour with protection circuit figure when applying most commonly required test pulses vehicle supply system. Pulse (ISO 7637) -100 only supplied TJA1010 behaviour during pulse Undervoltage shutdown, i.e. outputs off, falls below Otherwise operation unaffected. After shutdown: outputs off, desired output states restored Otherwise: Table TJA1010 behaviour with supply line transients (protection circuit figure connected) Overvoltage shutdown, i.e. outputs off, long Operation unaffected Overvoltage shutdown, i.e. outputs off, long Pulse (ISO 7637) 0.05 Pulses 3a/3b (ISO 7637) -150/+100V Clamped Load Dump
Pulse parameters
VBatt
TJA1010 functional status after pulse
Unchanged, i.e. prior pulse
1010 Octal Side Driver (OLSD)
SERIAL PERIPHERAL INTERFACE (SPI)
Application Note AN98057
Using serial instead parallel interface, allows control output stages with only instead pins (serial input, clock serial enable). adding further (serial output), possible read channel selective status information with only instead pins. Beyond that, serial interface allows cascading order drive several OLSDs without spending further microcontroller pins. Serial Peripheral Interface become industry standard serial synchronous interfaces between microcontrollers "slave devices" like smart power ICs. Many microcontrollers nowadays available with hardware implementation SPI, thus minimizing software effort drive this type interface. However, other microcontroller types, still emulated software.
Data Transfer between TJA1010 Microcontroller
block diagram figure shows, that basically consists ring register structure. ring register built 8-bit shift registers, implemented into microcontroller other into "slave device", here OLSD. There four interface signals: data signals control signals. latter provided microcontroller consist clock signal, linked with both shift registers enable signal OLSD. microcontroller with implemented SPI, clock signal generated unit. enable signal provided standard port pin.
Microcontroller
data clock
clock gen.
shift register
OLSD
Output Stage Out1 Out2
shift register
data Output Port enable
Latch
Out7 Out8
Fig. Connecting TJA1010 microcontroller
Table lists pins TJA1010 their functions. also shows names, which commonly used respective microcontroller pin, latter implemented SPI. Figure shows signals pins TJA1010, recorded during byte transfer. microcontroller initiates transfer applying low-level pin. This enables shift register serial input/ output operation. Then clock cycles generated microcontroller. Bits shifted both shift registers each low-to-high transient clock signal. Thus after clock cycle, both shift registers have exchanged their data. transfer finished, when microcontroller applies high-level pin. This disables serial input/output enables parallel loading data into 8-bit latch, which controls output stages. Bits received during transfer, control output stages out1 out8 respectively. high-level turns output stage Thus data received fig. indicate, that output stages 1,3,5,7 output stages 2,4,6,8 transfer.
1010 Octal Side Driver (OLSD)
Application Note AN98057
TJA1010 Description Serial Input data input control, high-level output stage Serial Output cascading diagnostics (sections Serial Clock Input shift each low-to-high transient Serial Input Enable low-level during data transfer Characteristic CMOS input
MICROCONTROLLER Respective Serial Output
open collector CMOS input CMOS input
Serial Input Clock Output Output Port
Table pins TJA1010 byte shifted output normally identical that byte, which been sent OLSD during previous transfer. however fault outputs been detected after that previous transfer, corresponding faulty output stage appears inverted Thus, channel selective diagnostic carried comparing received byte with byte, previously sent Section describes this more detail. waveforms fig. have been recorded while repetitively transferring same byte OLSD. data identical here, thus fault been detected. output also used cascading several OLSDs. This described section 5.3.
V/div
Output no.:
Time
Fig. signals during byte transfer
1010 Octal Side Driver (OLSD)
Controlling TJA1010 with Microcontroller
Application Note AN98057
Fig. shows instruction sequence microcontroller with implemented SPI, that will transfer control byte OLSD. Prior data transfer, system initialized operating modes, required TJA1010. Each data transfer started setting that port logic which connected TJA1010, enabling shift register serial transfer. After writing control byte OLSD into data register, circuit automatically generates clock cycles clock output. Bits shifted serial output pin, until both shift registers have exchanged their data. byte transfer, i.e. clock cycle indicated within microcontroller dedicated flag. When setting logic serial transfer TJA1010 disabled shift register data loaded into latch, control output stages.
Initialisation system
(clear dedicated port bit) write control byte into data register
transfer complete? (check dedicated flag) (set dedicated port bit)
Fig. Flow chart data transfer
Cascading OLSDs (Daisy Chain)
applications, where more than eight relays have controlled, allows cascading OLSDs form daisy chain, shown fig. Here, serial inputs outputs OLSDs connected build shift register with bytes. clock signal enable signal pins OLSDs parallel. Thus more than four microcontroller pins necessary drive principally unlimited number OLSDs. Fig. shows waveforms such daisy chain, consisting OLSDs. Basically, whole data transfer between microcontroller such daisy chain consists single byte transfers. Each single byte transfer functions already described sections 5.2. first byte OLSD last byte OLSD Before last byte been transferred, each OLSD shift register contains control data, which dedicated that device. Thus made sure, that shift register data cannot affect output stages, before last byte been transmitted. Therefore, pins OLSDs chain have kept permanently low-level, until last byte been transferred.
1010 Octal Side Driver (OLSD)
Application Note AN98057
Output Port Clock Microcontroller Serial Output Serial Input Fig. Daisy Chain OLSDs
OLSD
OLSD
OLSD
OLSD Serial Output Control byte Control byte Control byte Time
Fig. control signals daisy chain with OLSDs
DIAGNOSTICS
TJA1010 provides diagnostic information about loads, which connected output stages. Faults like "open load" (i.e. faulty connector, broken cable) "short circuit" (i.e. load shorted) detected reported microcontroller. following sections describe, faults detected signalled device evaluate these signals with microcontroller.
Diagnostic Functions TJA1010
block diagram fig. shows diagnostic functions TJA1010. Each output stage monitors load output voltage order detect open loads short circuit loads. such fault been detected, signalled shift register respective status output.
1010 Octal Side Driver (OLSD)
Application Note AN98057
VBatt Load short circuit
shift register
parallel outputs Latch
Output Stage
Out1 Out2 open load
Driver detector logic
parallel inputs
parallel load
Out7 Out8
Vref
delay
STATSC STATOL
Fig. Diagnostic functions
detector circuit compares output voltage with reference voltage Vref. this means, open load detected, output voltage below Vref off-state. pull-down current source each output provides defined output voltage case open load. short circuit load detected, output voltage above Vref on-state. "Soft" short circuit load overload conditions, that don't force output voltage above Vref onstate will detected, emergency temperature shutdown occurs protect device. that case, output voltage will also exceed Vref (see also section 3.2.2). comparator output each output stage linked with parallel input shift register. this means, shift register that output stage inverted, fault been detected. Thus, reading actual content shift register comparing with byte, which previously been written into channel selective diagnostic information derived, e.g. "open load output stage Table gives truth table this. dedicated detector logic each output stage evaluates control comparator output level that stage provides signals "sc" case short circuit load "ol" case open load. "sc" "ol" output stages linked with status outputs. Table shows, that STATSC STATOL deliver logic short circuit load open load have been detected output stage. Otherwise, status outputs logic STATSC delivers also logic emergency temperature shutdown (ETs) occurred "soft" short circuit load overload. Fig. shows, that status outputs only low-level, i.e. indicate fault, logic Thus, status outputs disabled during byte transfer, until pulled logic transfer. avoid erroneous status message switching event load output, enabling status outputs delayed about µsec.
1010 Octal Side Driver (OLSD)
Application Note AN98057
timing parallel loading fault information into shift register also determined SIE, shown fig. parallel loading only enabled logic level, fault information loaded beginning byte transfer. OLSD CONDITION OUTPUT Load Condition Output State "Soft short circuit load" emergency temperature shutdown (see section 3.2.2) Vout Vref Vref Vref Vref Vref Vref Vref Vref Vref DIAGNOSTIC SIGNALS Shift Register Output "Normal" "Open load" "Short circuit load"
STATOL
STATSC
Table Diagnostic truth table high-level, low-level; shaded cells indicate signals case fault detection)
Diagnostics with TJA1010 Microcontroller
TJA1010 reports diagnostic information microcontroller status outputs serial output easiest achieve channel selective diagnostic information (i.e. open load short circuit output stage), read required status output (STATOL, STATSC), shown fig. This done polling status output from port connecting status output interrupt input microcontroller. distinction between open load short circuit required, both status outputs parallelled, thus forming wired-or connection their open collector characteristic.
Microcontroller Port
TJA1010 short circuit
STATSC
Microcontroller Port
TJA1010 short circuit
STATSC
Port
STATOL open load
STATOL open load Short circuit open load output stage
Distinction between short circuit open load output stage
Fig. Diagnostics using status outputs
1010 Octal Side Driver (OLSD)
Application Note AN98057
Channel selective diagnostic information derived evaluating serial output data TJA1010 with microcontroller. this purpose, actual data received from TJA1010 (new bits) have compared with those previously sent TJA1010 (old bits). Table shows, that fault detection certain output stage indicated, respective position unequal. Otherwise, fault been detected. flow chart fig. shows diagnostic routine, which will find localize open load short circuit load output TJA1010. Note, that open loads only detected off-state short circuit loads only detected on-state. Therefore, output stages turned first test byte detect open loads then turned detect short circuit loads. diagnostic information then derived comparing respective test byte with byte received from during following transfer. Note, that released logic after transmission each test byte. This order write transferred byte into latch controlling output stages allow diagnostic circuits invert shift register bits, failures have been detected.
Microcontroller Action
Received Byte from OLSD (Example: open load OUT3, short circuit OUT7) OUT1.8
Comment
Send test byte 00000000
xxxxxxxx
Turn outputs off, enable open load detection. Turn outputs enable short circuit detection; received byte contains where open load been detected.
Send test byte 11111111
00100000
Store received byte
Send byte
11111101
Received byte contains where short circuit been detected.
Store received byte
Compare test bytes with received bytes derive diagnostic information Fig. Diagnostic routine high-level, low-level, don't care)
short circuit condition been detected, respective output stages case emergency temperature shutdown output stages should turned until failure been removed. Otherwise, operation device temperature protection levels over long time would reduce reliability.
1010 Octal Side Driver (OLSD)
MISCELLANEOUS Low-Power Mode
Application Note AN98057
low-power mode implemented into TJA1010, that minimizes current drawn device, therefore allows connect permanently battery. This mode entered pulling stand-by input STBY low-level. Note, that minimization battery current only achieved reducing supply current flowing into Vdd-pin. inputs outputs high-ohmic state low-power mode. currents pins low-power mode given data sheet.
Reset
TJA1010 reset microcontroller pulling stand-by input (STBY) low-level. This will turn output stages off. After pulling stand-by again high-level, this state remains, until control data transferred interface. TJA1010 also power-on reset function, i.e. output stages turn off, falls below undervoltage threshold level max. off-state remains, rises above again.
REFERENCE
Data Sheet: TJA1010 Octal Side Driver (OLSD), Philips Semiconductors (Feb 1998)

AN98057 1010 Octal Side Driver (OLSD) Application Note AN980

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