U6229B DC/DC Converter – Power Supply 28 V Description converter with external 150 mH inductivity to generate a 7-V auxiliary voltage with a small ripple. By means of this voltage, two linear regulators with only a small power dissipation provide a constant 5-V (±3%) supply for microcontrollers and an even more accurate 5-V (±2%) supply as a reference for sensors and a/d converters. The U6229B is a multifunctional power supply IC which provides four different voltages dedicated to supply components of complex microcontroller systems. Supplied by a battery voltage in the wide range from 6 V to 26 V, the U6229B generates typically 28.4 V with a step-up converter, PWM, external power MOSFET and 150 mH inductivity. This voltage is fed to a step-down Features D Voltage outputs – – – – D Analog input VKL15 v v 28.4-V step-up converter with I 1.2 A 7-V step-down converter with I 400 mA 5-V logic supply with I 14 mA 5-V reference voltage with I 14 mA v v D Logic input ENABLE – Energy-reserve mode switches off the step-up converter at VBatt < 5.25 V – Controls start-up behavior D Logic output NRES – N-reset output with over/ under voltage monitoring of both 5-V supplies – Enables the step-up converter Ordering Information Extended Type Number U6229B Package SO20 Remarks Block Diagram 28.4 V Supply VBatt VBL VA1 5V Logic supply 7V Supply VHL VH 5V Reference supply VCC VREF Step-down converter GATE PWM SOURCE Step-up converter Logic supply Reference voltage Internal reference Over / under voltage control VCC / VREF SGND Start-up circuit and over voltage protection VKL15 GND ENABLE Oscillator OSC RSET AGND NRES 96 12284 Figure 1. Block diagram with external circuit Rev. A1, 21-Apr-99 1 (8) Preliminary Information U6229B Pin Description Pin 1 2 3 4 5, 6, 15, 16, 17 7 8 9 10 11 12 13 14 18 19 20 Symbol OSC VBL VA1 SOURCE SGND GATE VHL VH VCC VREF NRES ENVA3 VKL15 AGND RSET1 GND Input / Output Analog input Analog input Analog output Analog input Ground Analog output Analog input Analog output Analog output Analog output Logic output Logic input Analog input Ground Analog input Ground Function Oscillator Input set-up converter Output set-up converter Source of switching transistor Ground Gate of switch transistor Output of power switch step-down converter Regulator input step-down converter 5-V supply voltage 5-V reference voltage Power-on reset Control step-up converter Monitoring supply voltage Reference ground Connect external resistor to GND – bias of the current sources Ground GND OSC 1 20 VBL 2 19 RSET1 VA1 3 18 AGND SOURCE 4 17 SGND SGND 5 16 SGND SGND 6 15 SGND GATE 7 14 VKl15 VHL 8 13 ENVA3 VH 9 12 NRES VCC 10 11 VREF Functional Description Oscillator, Pin 1 The switching frequency fosc is defined with (as) a triangle oscillator and is programmed with the capacitor COS1. fosc = Kosc/COS1 Step-up Converter VBL Pin 2, VA1 Pin 3 The step–up converter uses the battery voltage (6V to 26 V) to produce a constant output voltage (VA1 typ. 28.4 V). An external power MOSFET serves as the electronic power switch of the step–up converter. When this switch is activated, the coil current increases up to a limit determined by the controller. The power MOSFET is switched off when this limit is reached, and the energy stored in the coil is discharged into the capacitance CVA1 via the diode and the switches between VBL and VA1. The maximum possible coil current is limited to typ. 1.2 A by the circuit. Figure 2. Pinning U6229B 2 (8) Rev. A1, 21-Apr-99 Preliminary Information U6229B VBatt VA1 VKL15 VBL fosc Load-dump protection PWM VAI PWM VH VHL GATE CVA1 SOURCE CVH 96 12289 96 12288 Figure 3. Basic principle of the step-up converter SOURCE, Pin 4 A shunt resistor (typ. 180 mW) is connected between the SOURCE pin and SGND for measurement of the coil current of the step-up converter. SGND, Pins 5, 6, 15, 16 and 17 SGND is the power ground for the step-up and step-down converter. These pins are at the same time metallically connected to the chip carrier. This results in a very low thermal resistance of the package, which can be significantly improved by further external measures (large copper areas or heat sink/metal housing near these pins). GATE, Pin 7 The push-pull output Pin 7 is designed to trigger a power MOSFET.In order to protect the external FET, the maximum output voltage is limited by an integrated Zener diode. Step-down Converter VHL Pin 8, VH Pin 9 Figure 4. Basic principle of the step-down converter VCC, Pin 10 Output VCC supplies a 5-V voltage suitable for powering systems with microcontroller. The linear controller producing this voltage obtains its supply voltage from the voltage (VH) provided by the step-down converter. VCC is continuously monitored for any overvoltage or undervoltage. If such conditions occur, Pin NRES is switched to ’Low’ for this time. VREF is deactivated simultaneously. VREF, Pin 11 Output VREF supplies a precise output voltage of 5V (+/– 2%) (suitable, for example, as a reference voltage for an analog-to-digital converter). The linear controller producing this voltage obtains its supply voltage from the voltage (VH) provided by the step-down converter. VCC is continuously monitored for any overvoltage or undervoltage. If such conditions occur, Pin NRES is switched to ’Low’ for this time. NRES, Pin 12 The step-down converter produces a constant output voltage (VHtyp. 7 V) from the stepped-up voltage (VA1). When the integrated electronic power switch of the step-down converter (Pin VHL) is switched on, the coil current increases up to a limit determined by the controller. The switch is switched off when this limit is reached, and the energy stored in the coil is discharged into the capacitance CVH via an integrated diode. The circuit limits the maximum possible coil current to typ. 0.4 A. Pin VH is the controller input of the step-down converter. As mentioned, the voltages VCC and VREF are continuously monitored within narrow limits to detect any overvoltages or undervoltages. A reset signal is issued at output NRES if overvoltages or undervoltages occur. NRES = High: NRES = Low: Normal operation Reset state This function can trigger an error routine or a system reset in the event of disturbances.Pin NRES is an open collector output, which is protected by a 7-V Zener diode. Rev. A1, 21-Apr-99 3 (8) Preliminary Information U6229B ENVA3, Pin 13 extended interruptions in the supply voltage. The duration depends on the external load and the size of CVA1. Pin ENVA3 serves as the control input for the step-up converter AGND, Pin 18 ENVA3 = High/ open: Reference ground for voltages VA1, VH, VCC, VREF and internal reference ENVA3 = Low: Normal operation Step-up converter switched off VKl15, Pin 14 VKl15 fulfills several monitoring functions with regard to the supply voltage. – Overvoltage detection The external FET of the step–up converter and the switch between VA1 and VBL are switched off in the event of overvoltages of VBatt > 27 V typ. The other parts of the circuit continue to function and are powered by the capacitor connected to VA1 during this time. A Zener diode rated at typ. 23 V is integrated in Pin VKl15 to protect against overvoltages. – Energy reserve state The step-up converter is also switched off at battery voltages of VBatt < 5.25 V. This leads to a reduced current requirement from VA1. As the step-up converter and the two linear controllers VCC and VREF are powered by VA1, the circuit is able to power a system even in the event of RSET1, Pin 19 Pin 19 is connected to Pin 18 with a resistance of 35.7 kW (tolerance 1%). In the circuit, this resistance gives rise to a reference current from which various parameters such as the oscillator frequency, switch-off thresholds for step-up/step-down converter, threshold for overvoltage detection etc. are derived. GND, Pin 20 Common ground Starting Behavior The step-up converter is started only if the following start-up conditions are fulfilled when it is switched on: > 5.25 V typ. VBatt V3 > 3.4 V typ. > 3.6 V VBatt – V3 The step-down converter is activated only if V3 > 7 V typ. This ensures that the step-down converter begins operation only once the step-up converter has started. Absolute Maximum Ratings Parameters Supply voltage Ambient temperature range Junction temperature range Storage temperature range Symbol VBatt Tamb Tj Tstg Min. Typ. –40 –40 –55 Max. 44 95 150 150 Unit V °C °C °C Thermal Resistance Parameters Junction to case Junction ambient Symbol RthJC RthJA Value 30 90 Unit k/W k/W Overvoltage protection according DIN 40839/4 and ISO/TR 7637/1 ESD: HBM 2 kV: MIL 883D M.3015.7 MM 200 V: ESD S. 5.2 – 1994 4 (8) Rev. A1, 21-Apr-99 Preliminary Information U6229B Electrical Characteristics VBatt = 6 V to 26 V, Tamb = –40 to 95°C unless otherwise specified. Values measured at application example circuit figure 5. Parameters Oscillator Frequency constant Oscillator frequency Step-up converter Output voltage Test Conditions / Pins COS1 = 1 nF VCVB = 14 V Pin 3 I3 = 120 mA Output voltage VCVB > 5 V Pin 3 I3 = 30 mA Coefficient of efficiency VCVB = 5 V V3 = 27.5 V Coefficient of efficiency VCVB = 11 V V3 = 27.5 V Switch-off current LVB Pin 2 Voltage drop VBL – VA1; I2 = 0.9 I2max Voltage at pin GATE Output high Pin 7 Voltage at pin GATE Output low Pin 7 I7 = 100 mA Voltage at pin GATE Output low Pin 7 I7 = 5 mA Step-up converter – starting behavior Power-on-reset VBatt > 6 V Precharge CVA1 Step-up converter – Enable/Disable Supply voltage Threshold voltage V9 = 7 V Input voltage Pin 13 open Inpu current V13 = 0 V Step-down converter Output voltage I10 = –20 mA Pin 9 Coefficient of efficiency Switch-off current LVH Pin 8 Voltage drop VA1 – VHL; I8 = 0.9 I8max Forward voltage of freeIV8 = 0.9 I8max wheeling diode Step-down converter – starting behavior Switch threshold VBatt > 6 V VCC – regulator Output voltage IV10 = 0 mA to –90 mA Switch-off threshold Undervoltage Overvoltage Switch-on threshold Undervoltage Overvoltage Symbol Min. Typ. Max. Unit KOSC fOSC 73 89 HzmF kHz VVA1 27.5 28.4 29.3 V VVA1 27.5 28.4 29.3 V h 65 % h 82 % I2 V2 – V3 V7 V7 1.0 4.5 81 1.2 V7 1.6 3.5 18 1 A V V V 1.6 V V3 VBatt – V3 2.6 2.1 3.4 4.2 5.5 V V VBatt V13 V13 I13 5.5 0.8 4.4 – 1.9 5.25 5.5 2.0 7.0 – 0.4 V V V V VH 6.5 70 7.5 V % A V V h I8 V3 – V8 V8 – 0.4 – 0.65 1.3 – 1.2 V3 6.3 7.6 V V10 dV10off dV10off dV10on dV10on 4.85 5.15 230 230 V mV mV mV mV Rev. A1, 21-Apr-99 50 50 5 (8) Preliminary Information U6229B Parameters VREF – regulator Output voltage Switch-off threshold Test Conditions / Pins IV11 = –1 mA to –14 mA Undervoltage Overvoltage Undervoltage Overvoltage Switch-on threshold Symbol Min. V10 dV11off dV11off dV11on dV11on 4.88 VBatt 26 V14 21 Overvoltage protection Threshold for overvoltage detection Battery monitor VBatt = 40 V NRES Saturation voltage I12 = 1.6 mA, NRES = low Reverse current V12 = 5 V Typ. Max. Unit 5.12 150 150 V mV mV mV mV 28 V 26 V 0.4 2 V mA 50 50 V12 Ir12 23 VBatt RSET 35.7 kW 20 CVREF 2.2 mF RK15 249 W 19 18 17 16 15 14 13 12 5V Reference supply 11 RM 220 W U6229B BYG 10 BYG10 1 2 3 4 5 6 7 8 9 LVH 150 mH COS1 1 nF SI9955DY 7V Step-down converter 28.4 V Step-up converter LVB 150 mH CVB 100 mF 10 CVA1 1000 mF CVH 33 mF CVCC 15 mF 5V Logic supply 96 12285 Figure 5. Application example 6 (8) Rev. A1, 21-Apr-99 Preliminary Information U6229B V Batt Squib 28.4 V supply Power supply 4 Channel squib driver Sensor 5V reference ADC mC 5V logic 96 12290 Figure 6. System block diagram Package Information 9.15 8.65 Package SO20 Dimensions in mm 12.95 12.70 7.5 7.3 2.35 0.25 0.25 0.10 0.4 10.50 10.20 1.27 11.43 20 11 technical drawings according to DIN specifications 13038 1 10 Rev. A1, 21-Apr-99 7 (8) Preliminary Information U6229B Ozone Depleting Substances Policy Statement It is the policy of TEMIC Semiconductor 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 Semiconductor GmbH 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 Semiconductor GmbH 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 Semiconductors products for any unintended or unauthorized application, the buyer shall indemnify TEMIC Semiconductors 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 Semiconductor GmbH, P.O.B. 3535, D-74025 Heilbronn, Germany Telephone: 49 ( 0 ) 7131 67 2594, Fax number: 49 ( 0 ) 7131 67 2423 8 (8) Rev. A1, 21-Apr-99 Preliminary Information