 |
|
| If you can't view the Datasheet, Please click here to try to view without PDF Reader . |
|
|
|
| If you can't view the Datasheet, Please click here to try to view without PDF Reader . |
|
|
| Datasheet File OCR Text: |
| U6081B PWM Power Control with Low Duty Cycle Switch Off Description U6081B is a PWM IC in bipolar technology for the control of an N-channel power MOSFET used as a high side switch. The IC is ideal for the use in the brightness control (dimming) of lamps e.g., in dashboard applications. Features D Pulse width modulation up to 2 kHz clock frequency D Protection against short circuit, load dump overvoltage and reverse VS D Interference and damage protection according to VDE 0839 and ISO/TR 7637/1. D Duty cycle 0 to 100% D Output stage for power MOSFET D Ground wire breakage protection D Charge pump noise suppressed Ordering Information Extended Type Number U6081B Package DIP8 Remarks Block Diagram VS 1 5 Current monitoring + short circuit detection Charge pump 6 C5 Rsh VBatt C1 47 kW 4 RC oscillator PWM Logic Control input 7 C3 47 nF 8 Output C2 3 Duty cycle range 0/13 to 100 % 2 Voltage monitoring 95 9752 150 W R3 Ground Figure 1. Block diagram with external circuit TELEFUNKEN Semiconductors Rev. A1, 14-Feb-97 1 (8) U6081B Pin Description VS GND VI Osc 1 2 3 4 95 9944 8 7 6 5 Output 2 VS Sense Delay Pin 1 2 3 4 5 6 7 8 Symbol VS GND VI Osc Delay Sense 2 VS Output Function Supply voltage VS IC ground Control input (duty cycle) Oscillator Short circuit protection delay Current sensing Voltage doubler Output Functional Description 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 limitation of the IC is reduced from VS 26 V to VS 20 V. This leads to a hysteresis characteristic so that the loaddump detection is switched off again only at VBatt < 23 V. In this case the short-circuit protection is not in operation. Undervoltage Detection In the event of voltages of approximately VBatt < 5.0 V, the external FET is switched off and the latch for shortcircuit detection is reset. A hysteresis ensures that the FET is switched on again at approximately VBatt 5.4 V. R2 (see figure 2). Pin 3 is protected against short-circuit to VBatt and ground GND (VBatt 16.5 V). x 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: tf C4 I osc With VBatt = 12 V, C4 = 470 pF and Iosc = 40 mA, we thus obtain a controlled slope of r Batt + t +V r tf + t + 12 V 470 pF 40 mA + 141 ms A 100-W 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, C2. 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 I, from the charging current. The capacitor, C2, 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 Pin 2, GND Ground-Wire Breakage To protect the FET in the case of ground-wire breakage, a 820-kW resistor between gate and source is recommended to provide proper switch-off conditions. Pin 3, Control Input The pulse width is controlled by means of an external potentiometer (47 kW). 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 R1 and 2 (8) V T|100 V TL +V +V +V S S S + (V * I a + (V * I a + (V * I a 3 1 Batt S 2 Batt Batt S R 3) S a a 3 1 R 3) R 3) a 2 where TELEFUNKEN Semiconductors Rev. A1, 14-Feb-97 U6081B V T100 V Tt100 V TL + High switching threshold (100% duty cycle) + High switching threshold (t 100% duty cycle) + Low switching threshold 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 (VT2 90 mV), the duty cycle is switched over to 100% and the capacitor C5 is charged by a current source of 20 m A (Ich - Idis). The external FET is switched off after the cut-off threshold (VT5) is reached. Renewed switching on the FET is possible only after a power-on reset. The current source, Idis, ensures that the capacitor C5 is not charged by parasitic currents. The capacitor C5 is discharged by Idis to typ. 0.7 V. a1, a2 and a3 are fixed constant. The above mentioned threshold voltages are calculated for the following values given in the data sheet. VBatt = 12 V, IS = 4 mA, R3 = 150 W , a1 = 0.7, a2 = 0.67 and a3 = 0.28. + (12 V * 4 mA 150 W) V T100 0.7 [8 V V Tt100 V TL + 11.4 V 0.67 0.28 + 7.6 V Time delay, td, is as follows: td 5 T5 + 11.4 V + 3.2 V + + For a duty cycle of 100%, an oscillator frequency, f, is as follows: f + 330 nF @ (9.8 V * 0.7 V) 20 mA + 150 ms. td 2. Current Limitation With C5 = 330 nF and VT5 = 9.8 V, (Ich - Idis) = 20 mA, we have + C @ (V * 0.7 V) (I * I ch dis ) +2 +2 +2 +2 I osc (V T100 *V TL ) C2 , whereas C 2 22 nF 40 mA and I osc Therefore: f 40 mA (8 V 3.2 V) * + 189 Hz 22 nF The lamp current is limited by a control amplifier to protect 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 mV. Owing to the difference VT1 VT1-VT2 10 mV it is ensured that current limitation occurs only when the short circuit detection circuit has responded. [100 [ For a duty cycle of less than 100%, the oscillator frequency, f, is as follows: f (V Tt100 *V TL) I osc C2 )4 )4 V Batt C4 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. whereas f C4 = 470 pF (7.6 V * 3.2 V) 40 22 nF mA Pins 7 and 8, Charge Pump and Output 12 V 470 pF + 185 Hz A selection of different values of C2 and C4, provides a range of oscillator frequency, f, from 10 to 2000 Hz. 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 C3 (bootstrapping). Additionally, a trickle charge is generated by an integrated oscillator (f7 400 kHz) and a voltage doubler circuit. This permits a gate voltage supply at a duty cycle of 100%. TELEFUNKEN Semiconductors Rev. A1, 14-Feb-97 3 (8) U6081B Absolute Maximum Ratings Parameters Junction temperature Ambient temperature range Storage temperature range Symbol Tj Tamb Tstg Value 150 -40 to +110 -55 to +125 Unit C C C Thermal Resistance Parameters Junction ambient Symbol RthJA Maximum 120 Unit K/W Electrical Characteristics Tamb = -40 to +110C, 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). Test Conditions / Pins Pin 1 Overvoltage detection, stage 1 Stabilized voltage IS = 10 mA Pin 1 Battery undervoltage ON detection OFF Battery overvoltage detection Pin 2 Stage 1: - on - off Stage 2: - on - off Stabilized voltage IS = 30 mA Pin 1 Short-circuit protection Pin 6 Short-circuit current VT1 = VS - V6 limitation Short-circuit detection VT2 = VS - V6 Delay timer short-circuit detection, VBatt = 12 V Pin 5 Switched off threshold VT5 = VS - V5 Charge current Discharge current Capacitance current I5 = Ich - Idis Voltage doubler Pin 7 Voltage Duty cycle 100% Oscillator frequency Internal voltage limitation g I7 = 5 mA (whichever is lower) Parameters Current consumption Supply voltage Symbol IS VBatt VZ VBatt Min Typ Max 6.8 25 27.0 5.6 6.0 21.7 20.3 32.5 26.5 21.5 120 105 30 10.1 Unit mA V V V 24.5 4.4 4.8 18.3 16.7 25.5 19.5 18.5 85 75 3 9.5 5.0 5.4 20.0 18.5 28.5 23.0 20.0 100 90 10 9.8 23 3 20 VBatt VBatt VZ VT1 VT2 VT1 - VT2 VT5 Ich Idis I5 V7 f7 V7 V7 V V V mV mV mV V mA mA 27 mA 13 2 VS 280 26 VS+14 400 27.5 VS+15 520 30.0 VS+16 kHz V V 4 (8) TELEFUNKEN Semiconductors Rev. A1, 14-Feb-97 U6081B Parameters Test Conditions / Pins Switch-off at small duty cycles VBatt = 12 V Pin 3 Output disabled Output active Hysteresis switch-on Gate output Pin 8 Voltage g Low level VBatt = 16.5 V, Tamb = 110C, R3 = 150 W High level, duty cycle 100% Current V8 = Low level V8 = High level, I7 > | I8 | Oscillator Frequency Pin4 Threshold cycle V T100 V8 High, a 1 VS Upper V Tt100 V8 Low, a 2 VS Lower V TL a3 V S Oscillator current VBatt = 12 V Frequency tolerance C4 open, C2 = 470 nF, duty cycle = 50% Symbol V3/VS V3/VS DV3/VS V8 Min 0.3 0.32 0.004 0.35 Typ 0.32 0.34 Max 0.34 0.36 0.032 0.95 1.5 *) V Unit 0.70 V8 I8 1.0 -1.0 10 0.68 0.65 0.26 34 6.0 V7 mA + + + + + a1 a2 a3 f 0.7 0.67 0.28 45 9.9 2000 0.72 0.69 0.3 54 13.5 Hz Iosc f mA Hz *) Reference point is battery ground TELEFUNKEN Semiconductors Rev. A1, 14-Feb-97 5 (8) U6081B Package Information Package DIP8 Dimensions in mm 9.8 9.5 1.64 1.44 7.77 7.47 4.8 max 6.4 max 0.5 min 0.58 0.48 7.62 8 5 2.54 3.3 0.36 max 9.8 8.2 technical drawings according to DIN specifications 13021 1 4 6 (8) TELEFUNKEN Semiconductors Rev. A1, 14-Feb-97 Application VBatt 100 W C5 330 nF 5 VS VS + + - + I + 6 Oscillator Idis - + Reset 2I Switch - on delay 7 C3 Duty factor = 10% - + Overvoltage monitoring stage 2 - Reset Low voltage monitoring 2 150 W + 8 820 k W 47 nF 1 VS VS 90 mV C4 470 pF 10 mV Ich - Current limiting VS Rsh TELEFUNKEN Semiconductors Rev. A1, 14-Feb-97 VS - VS Voltage doubler Reset - + Overvoltage monitoring stage 1 R3 Ground Load RL C1 4 47 m F R1 C2 Figure 2. 22 nF 47 kW 3 30 k W R2 VS VS U6081B 95 9759 7 (8) U6081B 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 8 (8) TELEFUNKEN Semiconductors Rev. A1, 14-Feb-97 |
Price & Availability of U6081B
 |
|
|
|
|
All Rights Reserved © IC-ON-LINE 2003 - 2022 |
| [Add Bookmark] [Contact Us] [Link exchange] [Privacy policy] |
|
Mirror Sites : [www.datasheet.hk]
[www.maxim4u.com] [www.ic-on-line.cn]
[www.ic-on-line.com] [www.ic-on-line.net]
[www.alldatasheet.com.cn]
[www.gdcy.com]
[www.gdcy.net] |