U6081B

U6081B TEMIC | Alldatasheet

Document overview

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Technical content

Features

/C0068Pulse width modulation up to 2 kHz clock frequency /C0068Protection against short circuit, load dump overvol- tage and reverse VS /C0068Duty cycle 0 to 100% /C0068Output stage for power MOSFET /C0068Interference and damage protection according to VDE 0839 and ISO/TR 7637/1. /C0068Ground wire breakage protection /C0068Charge pump noise suppressed

Ordering Information

Extended Type Number Package Remarks U6081B DIP8 Block Diagram Current monitoring + short circuit detection Output Charge pumpRC oscillator Duty cycle range 0/13 to 100 % Control input V oltage monitoring V S C 5 PWM Logic 47 k/C0087 47 nF R sh R 3150 /C0087 95 9752 V Batt C 3 C 2 C 1 Ground Figure 1. Block diagram with external circuit

Rev. A1, 14-Feb-97 2 (8) Pin Description 4 5 95 9944 V S GND V I Osc Output Sense 2 VS Delay Pin Symbol Function

1 V S Supply voltage VS

2 GND IC ground

3 V I Control input (duty cycle)

4 Osc Oscillator

5 Delay Short circuit protection delay

6 Sense Current sensing

8 Output Output

Pin 1, Supply Voltage, Vs or VBatt Overvoltage Detection Stage 1: If VBatt > 20 V occurs the external transistor will be switched off and switched on again at VBatt < 18.5 V (hysteresis). Stage 2: If VBatt > 28 V , the external transistor is switched on again (load-dump protection). At the same time the voltage li- mitation of the IC is reduced from V S ≈ 26 V to VS ≈ 20 V . This leads to a hysteresis characteristic so that the load- dump detection is switched off again only at V Batt < 23 V . In this case the short–circuit protection is not in operation. Undervoltage Detection In the event of voltages of approximately V Batt < 5.0 V , the external FET is switched off and the latch for short- circuit detection is reset. A hysteresis ensures that the FET is switched on again at approximately V Batt /C0021 5.4 V . Pin 2, GND Ground-Wire Breakage To protect the FET in the case of ground-wire breakage, a 820-k/C0087 resistor between gate and source is recom- mended to provide proper switch-off conditions. Pin 3, Control Input The pulse width is controlled by means of an external potentiometer (47 k/C0087). The characteristic (angle of rotation/duty cycle) is linear. The duty cycle can be varied from 0 to 100%. To avoid inadmissibly high filament cold currents, the dimmer is switched off at duty cycles of approximately < 10% or is switched on only at duty cycles of approximately > 13% (hysteresis). It is possible to further restrict the duty cycle with the resistors R 1 and R 2 (see figure 2). Pin 3 is protected against short-circuit to VBatt and ground GND (VBatt /C0120 16.5 V). Output Slope Control The rise and fall time (tr, tf) of the lamp voltage can be limited to reduce radio interference. This is done with an integrator which controls a power MOSFET as source follower. The slope time is controlled by an external capacitor C4 and the oscillator current (see figure 2). Calculation: t f /C0043tr /C0043V Batt /C0032C 4 Iosc With VBatt = 12 V , C4 = 470 pF and Iosc = 40 /C0109A, we thus obtain a controlled slope of tf /C0043tr /C004312 V /C0032470 pF 40 /C0109A /C0043141 /C0109s A 100-/C0087 resistor in series to C4 is recomended to damp device oscillations (see figure 2). Pin 4, Oscillator The oscillator determines the frequency of the output voltage. This is defined by an external capacitor, C 2. It is charged with a constant current, I, until the upper switching threshold is reached. A second current source is then activated which taps a double current, 2/C0032I, from the charging current. The capacitor, C 2, is thus discharged by the current, I, until the lower switching threshold is reached. The second source is then switched off again and the procedure starts again. Example for oscillator frequency calculation: V T100 /C0043V S /C0032/C00971 /C0043(V Batt /C0042IS /C0032R 3) /C0032/C00971 V T/C0166100 /C0043V S /C0032/C00972 /C0043(V Batt /C0042IS /C0032R 3) /C0032/C00972 V TL /C0043V S /C0032/C00973 /C0043(V Batt /C0042IS /C0032R 3) /C0032/C00973 where

Rev. A1, 14-Feb-97 3 (8) V T100 /C0043High switching threshold (100% duty cycle) V T/C0116100 /C0043High switching threshold(/C0116100% duty cycle) V TL /C0043Low switching threshold /C00971, /C00972 and /C00973 are fixed constant. The above mentioned threshold voltages are calculated for the following values given in the data sheet. V Batt = 12 V , IS = 4 mA, R3 = 150 /C0087 , /C00971 = 0.7, /C00972 = 0.67 and /C00973 = 0.28. V T100 /C0043(12 V /C00424m A /C0032150 /C0087) /C00320.7 /C00918V V T/C0116100 /C004311.4 V /C00320.67 /C00437.6 V V TL /C004311.4 V /C00320.28 /C00433.2 V For a duty cycle of 100%, an oscillator frequency, f, is as follows: f/C0043 Iosc 2 /C0032(V T100 /C0042V TL )/C0032C 2 ,w h e r e a s C2 /C004322 nF and I osc /C004340 /C0109A Therefore: f/C0043 40 /C0109A 2 /C0032(8V /C00423.2 V)/C003222 nF /C0043189 Hz For a duty cycle of less than 100%, the oscillator frequency, f, is as follows: f/C0043 Iosc 2 /C0032(V T/C0116100 /C0042V TL )/C0032C 2 /C00414 /C0032V Batt/C0032C 4 whereas C 4 = 470 pF f/C0043 40 /C0109A 2 /C0032(7.6 V/C00423.2 V)/C003222 nF /C00414 /C003212 V /C0032470 pF /C0043185 Hz A selection of different values of C2 and C4, provides a range of oscillator frequency, f, from 10 to 2000 Hz. Pins 5 and 6, Short-Circuit Protection and Current Sensing 1. Short-Circuit Detection and Time Delay, td The lamp current is monitored by means of an external shunt resistor. If the lamp current exceeds the threshold for the short-circuit detection circuit (V T2 /C0025 90 mV), the duty cycle is switched over to 100% and the capacitor C5 is charged by a current source of 20 /C0109 A (Ich – Idis). The external FET is switched off after the cut-off threshold T5) is reached. Renewed switching on the FET is possible only after a power-on reset. The current source, I dis, ensures that the capacitor C5 is not charged by parasitic currents. The capacitor C5 is discharged by Idis to typ. 0.7 V . Time delay, td, is as follows: td /C0043C 5 /C0064(V T5 /C00420.7 V)/C0324(Ich /C0042Idis) With C5 = 330 nF and VT5 = 9.8 V , (Ich – Idis) = 20 /C0109A, we have td /C0043330 nF /C0064(9.8 V /C00420.7 V)/C032420 /C0109A /C0043150 ms. 2. Current Limitation The lamp current is limited by a control amplifier to pro- tect the external power transistor. The voltage drop across an external shunt resistor acts as the measured variable. Current limitation takes place for a voltage drop of V T1 /C0091100 mV . Owing to the difference V T1–V T2 /C009110 mV it is ensured that current limitation occurs only when the short circuit detection circuit has responded. After a power-on reset, the output is inactive for an half oscillator cycle. During this time, the supply voltage capacitor can be charged so that the current limitation is guaranteed in the event of a short circuit when the IC is switched on for the first time. Pins 7 and 8, Charge Pump and Output Output, Pin 8, is suitable for controlling a power MOSFET. During the active integration phase, the supply current of the operational amplifier is mainly supplied by the capacitor C 3 (bootstrapping). Additionally, a trickle charge is generated by an integrated oscillator 7 /C0025/C0032400 kHz) and a voltage doubler circuit. This permits a gate voltage supply at a duty cycle of 100%.

Rev. A1, 14-Feb-97 4 (8) Absolute Maximum Ratings Parameters Symbol Value Unit Junction temperature Tj 150 °C Ambient temperature range Tamb –40 to +110 °C Storage temperature range Tstg –55 to +125 °C Thermal Resistance Parameters Symbol Maximum Unit Junction ambient R thJA 120 K/W

Electrical Characteristics

Tamb = –40 to +110°C, VBatt = 9 to 16.5 V , (basic function is guaranteed between 6.0 V to 9.0 V) reference point is ground, unless otherwise specified (see figure 1). All other values refer to Pin GND (Pin 2). Parameters Test Conditions / Pins Symbol Min Typ Max Unit Current consumption Pin 1 IS 6.8 mA Supply voltage Overvoltage detection, stage 1 V Batt 25 V Stabilized voltage IS = 10 mA Pin 1 V Z 24.5 27.0 V Battery undervoltage detection ON OFF V Batt 4.4 4.8 5.0 5.4 5.6 6.0 V Battery overvoltage detection Pin 2 Stage 1: – on – off V Batt 18.3 16.7 20.0 18.5 21.7 20.3 V Stage 2: – on – off V Batt 25.5 19.5 28.5 23.0 32.5 26.5 V Stabilized voltage IS = 30 mA Pin 1 V Z 18.5 20.0 21.5 V Short-circuit protection Pin 6 Short-circuit current limitation V T1 = VS – V6 V T1 85 100 120 mV Short-circuit detection V T2 = VS – V6 V T2 75 90 105 mVT2 S 6 V T1 – VT2 3 10 30 mV Delay timer short-circuit detection, VBatt = 12 V Pin 5 Switched off threshold V T5 = VS – V5 V T5 9.5 9.8 10.1 V Charge current Ich 23 /C0109A Discharge current Idis 3 /C0109A Capacitance current I5 = Ich – Idis I5 13 20 27 mA Voltage doubler Pin 7 V oltage Duty cycle 100% V 7 2 VS Oscillator frequency f7 280 400 520 kHz Internal voltage limitationI7 = 5 mA V 7 26 27.5 30.0 Vg (whichever is lower) V 7 V S+14 V S+15 V S+16 V

Rev. A1, 14-Feb-97 5 (8) Parameters Test Conditions / Pins Symbol Min Typ Max Unit Switch-off at small duty cycles VBatt = 12 V Pin 3 Output disabled V 3/VS 0.3 0.32 0.34 Output active V 3/VS 0.32 0.34 0.36 Hysteresis switch-on /C0068V 3/VS 0.004 0.032 Gate output Pin 8 V oltage Low level V 8 0.35 0.70 0.95 Vg V Batt = 16.5 V , Tamb = 110°C, R3 = 150 /C0087 1.5 *) High level, duty cycle 100% V 8 V 7 Current V 8 = Low level I8 1.0 mA V 8 = High level, I7 > | I8 | –1.0 Oscillator Frequency Pin4 f 10 2000 Hz Threshold cycle Upper V 8 /C0043High, /C00971 /C0043V T100 V S /C00971 0.68 0.7 0.72 Upper V 8 /C0043Low, /C00972 /C0043V T/C0116100 V S /C00972 0.65 0.67 0.69 Lower /C00973 /C0043V TL V S /C00973 0.26 0.28 0.3 Oscillator current V Batt = 12 V /C0006Iosc 34 45 54 /C0109A Frequency tolerance C 4 open, C2 = 470 nF, duty cycle = 50% f 6.0 9.9 13.5 Hz *) Reference point is battery ground

Rev. A1, 14-Feb-97 6 (8)

Package Information

9.8 9.5 Dimensions in mm 1.64 1.44 4.8 max 0.5 min 3.3 0.58 0.48 7.62 2.54 6.4 max 0.36 max 9.8 8.2 7.77 7.47 technical drawings according to DIN specifications

Rev. A1, 14-Feb-97 7 (8) Application V S Reset V S V S Ich Reset Switch – on delay 2 I V S I Oscillator 30 k/C0087 100 /C0087 V S Overvoltage monitoring stage 1 Low voltage monitoring V S V S Reset Overvoltage monitoring stage 2 V oltage doubler V S 90 mV 10 mV V S Current limiting 47 nF 820 k/C0087 R sh V BattC 5 R3150 /C0087 Ground R 1 R 2 C 2 47 k/C0087 47 F Load R L Idis 95 9759 Duty factor = 10% /C0109 470 pF 330 nF 22 nF Figure 2.

Rev. A1, 14-Feb-97 8 (8) Ozone Depleting Substances Policy Statement It is the policy of TEMIC TELEFUNKEN microelectronic GmbH to 1. Meet all present and future national and international statutory requirements. 2. Regularly and continuously improve the performance of our products, processes, distribution and operating systems with respect to their impact on the health and safety of our employees and the public, as well as their impact on the environment. It is particular concern to control or eliminate releases of those substances into the atmosphere which are known as ozone depleting substances (ODSs). The Montreal Protocol (1987) and its London Amendments (1990) intend to severely restrict the use of ODSs and forbid their use within the next ten years. Various national and international initiatives are pressing for an earlier ban on these substances. TEMIC TELEFUNKEN microelectronic GmbH semiconductor division has been able to use its policy of continuous improvements to eliminate the use of ODSs listed in the following documents. 1. Annex A, B and list of transitional substances of the Montreal Protocol and the London Amendments respectively 2. Class I and II ozone depleting substances in the Clean Air Act Amendments of 1990 by the Environmental Protection Agency (EPA) in the USA 3. Council Decision 88/540/EEC and 91/690/EEC Annex A, B and C (transitional substances) respectively. TEMIC can certify that our semiconductors are not manufactured with ozone depleting substances and do not contain such substances. We reserve the right to make changes to improve technical design and may do so without further notice. Parameters can vary in different applications. All operating parameters must be validated for each customer application by the customer. Should the buyer use TEMIC products for any unintended or unauthorized application, the buyer shall indemnify TEMIC against all claims, costs, damages, and expenses, arising out of, directly or indirectly, any claim of personal damage, injury or death associated with such unintended or unauthorized use. TEMIC TELEFUNKEN microelectronic GmbH, P.O.B. 3535, D-74025 Heilbronn, Germany Telephone: 49 (0)7131 67 2831, Fax number: 49 (0)7131 67 2423