HT7936A/HT7936B White LED Step-up Charge Pump Converter Features · Input voltage range: 2.8V to VOUT · Oscillator frequency: 1MHz · Driving current: 110mA (HT7936A), · Soft start function, current limit, 150mA (HT7936B) · Fixed output voltage: 5V (HT7936A), 4.5V (HT7936B) · Small outline SOT23-6 package short circuit protection Applications · Cellular phones · Handheld devices · PDAs · White LED display backlighting · DSCs General Description The HT7936A and HT7936B are charge-pump type DC-DC step-up converter devices, which can generate regulated fixed output voltages of 5.0V and 4.5V. Their high degree of functional integration requires only the addition of three external capacitors, namely a flying capacitor and an input and output capacitor, to implement a full step-up conversion function. during device power on. The operating voltage range is from 2.8V to the full output voltage value, VOUT. To meet the demands of today¢s power sensitive applications, the devices, have a very low standby current value as well as the extra safety features of current limit and short circuit protection. This range of device features, supplied in 6-pin SOT-23-6 package type, will ensure that these device will find excellent use in a wide range of DC-DC step-up converter applications. The devices have the additional benefit of an integrated soft start function to reduce the level of in-rush current Selection Table Note: Part No. Output Voltage Tolerance Package Marking HT7936A 5.0V ±4% SOT23-6 936A# 936A+ HT7936B 4.5V ±4% SOT23-6 936B# 936B+ Both lead free and green compound devices are available. ²#² stands for Lead-free devices. ²+² stands for green compound devices, which are Lead-free and Halogen-free. Rev 1.20 1 November 6, 2013 HT7936A/HT7936B Block Diagram C + V IN M 4 C - M 1 M 2 M 3 S h o r t C ir c u it P r o te c io n V O U T C o n tro l G N D E N V R E F 1 M H z O S C N o te : D u r in g o p e r a tio n th e fo llo w in g s e q u e n c e o c c u r s : 1 . M 1 , M 3 O n / M 2 , M 4 O ff 2 . M 2 , M 4 O n / M 1 , M 3 O ff Pin Assignment S O T 2 3 -6 C + 6 C 4 V IN 5 9 3 6 X 1 2 V O U T G N D T o p V ie w 3 E N Pin Description Pin No. Pin Name Description Regulated Output Voltage. VOUT should be bypassed with a 1mF to 10mF low ESR ceramic capacitor placed as close as possible to the pin for best performance. 1 VOUT 2 GND Ground. This pin is the voltage reference for the regulator output voltage. 3 EN Device On/Off Control 1: Enable 0: Disable Pin must not be left floating. 4 C- Capacitor Negative Pin. Flying capacitor negative terminal. 5 VIN Input Supply Voltage. VIN should be bypassed with a 1mF to 10mF low ESR ceramic capacitor. 6 C+ Capacitor Positive Pin. Flying capacitor positive terminal. Rev 1.20 2 November 6, 2013 HT7936A/HT7936B Absolute Maximum Ratings Input Supply Voltage..................................................6V Other Pins Voltage ....................................................6V Operating Temperature Range ...............-40°C to 85°C Maximum Junction Temperature..........................125°C Note: These are stress ratings only. Stresses exceeding the range specified under ²Absolute Maximum Ratings² may cause substantial damage to the device. Functional operation of this device at other conditions beyond those listed in the specification is not implied and prolonged exposure to extreme conditions may affect device reliability. Electrical Characteristics Symbol VIN VIN=VEN=3.7V, CIN=CPUMP=COUT=1mF, Ta=25°C, unless otherwise specified. Parameter Test Conditions Min. Typ. Max. Unit HT7936A 2.8 ¾ 5.0 V HT7936B 2.8 ¾ 4.5 V HT7936A, VIN>3.2V, IO£110mA 4.80 ¾ 5.20 V HT7936B, VIN>3.2V, IO£140mA 4.32 ¾ 4.68 V Input Supply Voltage VOUT Output Voltage ISHDN Shutdown Current VEN=0 ¾ 0.1 1.0 mA IQ Operation Current ¾ ¾ 2.0 4.0 mA IO HT7936A 110 ¾ ¾ mA Output Current HT7936B 150 ¾ ¾ mA ISHORT Short Circuit Current ¾ ¾ 60 90 mA ILIMIT Current Limit ¾ ¾ 370 500 mA fOSC Switching Frequency ¾ 0.8 1.0 1.3 MHz VENH EN Pin Voltage High 2.8V £ VIN £ 5.0V 1.5 ¾ ¾ V VENL EN Pin Voltage Low 2.8V £ VIN £ 5.0V ¾ ¾ 0.4 V VRIPPLE Output Ripple Voltage IO=60mA, COUT=2.2mF ¾ 30 ¾ mV h HT7936A, VIN=3.0V, IO=50mA ¾ 80 ¾ % Efficiency HT7936B, VIN=2.8V, IO=70mA ¾ 80 ¾ % Note: Absolute maximum ratings indicate limits beyond which damage to the device may occur. Operating Ratings indicate conditions for which the device is intended to be functional, but do not guarantee specific performance limits. The guaranteed specifications apply only for the test conditions listed. Specifications are production tested at Ta=25°C. Specifications over -40°C to +85°C operating temperature range are assured by design. Rev 1.20 3 November 6, 2013 HT7936A/HT7936B Functional Description These DC-DC step-up converters can generate fixed level output voltages higher than their input supply voltage. Capacitor Selection Careful selection of the three external capacitors CIN, COUT and CPUMP is important because they will affect ramp-up time, output ripple and transient performance. Optimum performance will be obtained when low ESR (<100mW) ceramic capacitors are used for CIN and COUT and CPUMP. Operation Utilising a charge pump method with three external capacitors to store and transfer energy, the devices can transfer electrical energy from input to output at different voltage levels. Since the capacitors are not able to change their voltage level abruptly, the VOUT/VIN voltage ratio of VOUT over VIN is limited within a fixed range. Capacitive voltage conversion is obtained by the periodic switching of a capacitor. It first charges the capacitor CPUMP by connecting it across a voltage source after which it is connected to the output. Referring to Figure.1, during the on state of the internal clock, M1 and M3 are closed, M2 and M4 are opened, which charges CPUMP to a VIN level. During the off state of the internal clock, M2 and M4 are closed, M1 and M3 are opened, which transfers the energy to the output. The output voltage is therefore VIN plus VCPUMP, which is in effect equal to 2VIN. V IN C IN M 1 C M 2 P U M P M 4 C V In general, a low ESR may be defined as less than 100mW. In all cases, X7R or X5R dielectrics are recommended. For certain applications, low ESR Tantalum capacitors may be substituted, however optimum output ripple performance may not be attainable. Aluminum electrolytic capacitors are not recommended for use with these devices due to their inherent high ESR characteristics. In general the CIN, COUT and CPUMP capacitors may range from 1mF to 10mF for heavy output load conditions. If the CPUMP capacitor is increased, then COUT should also be increased by the same ratio to minimise output ripple. Lowering the values of CIN, COUT and CPUMP may decrease the ramp-up time of VOUT, but it will inversely increase the output ripple. O U T O U T Efficiency M 3 The efficiency of the charge pump regulator varies with the output voltage type, the applied input voltage, the load current and the internal operation mode of the device. Figure.1 Shutdown The approximate device efficiency is given by: The devices can be shutdown by setting the EN input pin to a low level. In the shutdown mode, the output is disconnected from the input. The input current will reduce to an extremely low level as most of the internal circuitry is inactive. As the EN pin is a high impedance input, it must not be allowed to float. Short Circuit Protection The devices contain integrated short circuit protection circuits with current limiting protection. During a short circuit condition, the output current is automatically limited to a typical value of approximately 60mA. If the fault does not clear itself, the protect operation will repeat continuously. This protection feature allows the devices to operate indefinitely under short circuit conditions without damaging the device. Rev 1.20 Due to internal switching losses and IC quiescent current consumption, the actual measured efficiency will decrease. 4 November 6, 2013 HT7936A/HT7936B Typical Operating Characteristics For HT7936A, CIN=COUT=2.2mF, CPUMP=0.22mF, Ta=25°C, unless otherwise specified HT7936A Output Voltage vs. Output Current 5.1 Output Voltage(V) 5.0 4.9 VIN=2.8V 4.8 VIN=3V VIN=3.2V 4.7 VIN=3.7V 4.6 VIN=4.2V 4.5 VIN=5V 4.4 4.3 10 20 30 40 50 60 70 80 90 100 110 Output Current(mA) HT7936A Operation Current vs. Input Voltage Quiescent Current(mA) 2.2 2.1 2.0 1.9 IQ IQ 1.8 1.7 1.6 1.5 2.8 3.0 3.3 3.5 3.8 4.0 4.3 4.5 4.8 5.0 Input Voltage(V) Rev 1.20 5 November 6, 2013 HT7936A/HT7936B H T 7 9 3 6 A O u tp u t V o lta g e v s . S u p p ly V o lta g e 5 .1 I OO II OO I OO II OO I OO II OO I OO IO IO II OO II OO O u tp u t V o lta g e (V ) 5 .0 4 .9 4 .8 4 .7 4 .6 4 .5 4 .4 4 .3 2 .7 5 3 .0 0 3 .2 5 3 .5 0 3 .7 5 4 .0 0 4 .2 5 4 .5 0 S u p p ly V o lta g e (V ) 4 .7 5 = 1 == 22 = 3 == 44 = 5 == 66 = 7 = 8 = 9 == 11 = 1 0 m 00 mm 0 m 00 mm 0 m 00 mm 0 m 0 m 0 m 00 00 1 0 A AA A AA A AA A A A mm AA m AA 5 .0 0 H T 7 9 3 6 A E ffic ie n c y v s . O u tp u t C u r r e n t 9 0 % 8 5 % 8 0 % V IN V IN V IN V IN V IN V IN E ffic ie n c y 7 5 % 7 0 % 6 5 % 6 0 % 5 5 % 5 0 % = 2 .8 = 3 V = 3 .2 = 3 .7 = 4 .2 = 5 V V V V V 4 5 % 4 0 % 1 0 2 0 3 0 4 0 5 0 6 0 7 0 8 0 O u tp u t C u rre n t(m A ) H T 7 9 3 6 A 9 0 1 0 0 1 1 0 E ffic ie n c y v s . In p u t V o lta g e 9 0 % IO II OO I OO II OO I OO II OO IO IO IO II OO I OO 8 5 % 8 0 % E ffic ie n c y 7 5 % 7 0 % 6 5 % 6 0 % 5 5 % 5 0 % 4 5 % 4 0 % Rev 1.20 2 .7 5 3 .0 0 3 .2 5 3 .5 0 3 .7 5 4 .0 0 4 .2 5 In p u t V o lta g e (V ) 6 4 .5 0 4 .7 5 = 1 == 22 = 3 == 44 = 5 == 66 = 7 = 8 = 9 == 11 = 1 0 m 00 mm 0 m 00 mm 0 m 00 mm 0 m 0 m 0 m 00 00 1 0 A AA A AA A AA A A A mm AA m A 5 .0 0 November 6, 2013 HT7936A/HT7936B For HT7936B, CIN=COUT=2.2mF, CPUMP=0.22mF, Ta=25°C, unless otherwise specified HT7936B Output Voltage vs. Output Current 4.6 Output Voltage(V) 4.5 4.4 4.3 VIN=2.8V 4.2 VIN=3V VIN=3.2V 4.1 VIN=3.7V 4.0 VIN=4.5V 3.9 3.8 3.7 10 25 40 55 70 85 100 115 130 145 Output Current(mA) HT7936B Operation Current vs. Input Voltage Quiescent Current(mA) 2.2 2.1 2.0 1.9 IQ IQ 1.8 1.7 1.6 1.5 2.8 3.0 3.3 3.5 3.8 4.0 4.3 4.5 Input Voltage(V) Rev 1.20 7 November 6, 2013 HT7936A/HT7936B Output Voltage(V) HT7936B Output Voltage vs. Supply Voltage IO=10mA 4.6 IO=20mA 4.5 IO=30mA IO=40mA 4.4 IO=50mA 4.3 4.2 IO=60mA IO=70mA 4.1 IO=80mA 4.0 IO=90mA 3.9 IO=100mA IO=110mA 3.8 IO=120mA 3.7 2.8 3.0 3.3 3.5 3.8 4.0 4.3 4.5 IO=130mA IO=140mA Supply Voltage(V) IO=150mA HT7936B Efficiency vs. Output Current 85% 80% Efficiency 75% 70% VIN=2.8V 65% VIN=3V VIN=3.2V 60% VIN=3.7V 55% VIN=4.5V 50% 45% 40% 10 25 40 55 70 85 100 115 130 145 Output Current(mA) HT7936B Efficiency vs. Input Voltage IO=20mA 85% IO=30mA 80% IO=40mA IO=50mA Efficiency 75% 70% IO=60mA 65% IO=70mA 60% 55% IO=80mA IO=90mA 50% IO=100mA 45% IO=110mA 40% IO=120mA 2.8 3.0 3.3 3.5 3.8 Input Voltage(V) Rev 1.20 IO=10mA 8 4.0 4.3 4.5 IO=130mA IO=140mA IO=150mA November 6, 2013 HT7936A/HT7936B Inrush Current HT7936A VIN=2.8V, CIN=COUT=2.2mF, CPUMP=0.22mF HT7936B VIN=2.8V, CIN=COUT=2.2mF, CPUMP=0.22mF HT7936A VIN=5.0V, CIN=COUT=2.2mF, CPUMP=0.22mF HT7936B VIN=4.5V, CIN=COUT=2.2mF, CPUMP=0.22mF Rev 1.20 9 November 6, 2013 HT7936A/HT7936B Normal Operation HT7936A VIN=2.8V, CIN=COUT=2.2mF, CPUMP=0.22mF HT7936B VIN=2.8V, CIN=COUT=2.2mF, CPUMP=0.22mF HT7936A VIN=5.0V, CIN=COUT=2.2mF, CPUMP=0.22mF HT7936B VIN=4.5V, CIN=COUT=2.2mF, CPUMP=0.22mF Rev 1.20 10 November 6, 2013 HT7936A/HT7936B Dimming Operation HT7936A, Refer to Figure.2 V IN 3 .7 V C IN 1 m F C C + P U M P 1 m F V IN H T 7 9 3 6 A C - E N V O U T G N D C O U 1 m F R 1 1 0 0 W T L E D 3 V 0 V P W M 1 0 0 H z ~ 1 5 k H z R 2 1 0 0 W L E D R 3 1 0 0 W L E D Q 1 Figure.2 Rev 1.20 11 November 6, 2013 HT7936A/HT7936B HT7936A, Refer to Figure.3 V C IN 3 .7 V C + C IN 1 m F H T 7 9 3 6 A P U M P 1 m F P W M V IN C - 5 0 0 H z 3 V 0 V E N V O U T G N D C R 1 1 0 0 W O U T 1 m F L E D R 2 1 0 0 W L E D R 3 1 0 0 W L E D Figure.3 Application Circuits 2 .8 V to V V C IN O U T C IN C + P U M P C - V IN E N H T 7 9 3 6 A H T 7 9 3 6 B V O U T G N D N o te : C Rev 1.20 IN = C P U M P = C O U T = 1 m F (T A IY O Y U D E N C R L E D L E D L E D O U T J M K 1 0 7 B J 1 0 5 K A ) 12 November 6, 2013 HT7936A/HT7936B Package Information Note that the package information provided here is for consultation purposes only. As this information may be updated at regular intervals users are reminded to consult the Holtek website for the latest version of the package information. Additional supplementary information with regard to packaging is listed below. Click on the relevant section to be transferred to the relevant website page. · Further Package Information (include Outline Dimensions, Product Tape and Reel Specifications) · Packing Meterials Information · Carton information · PB FREE Products · Green Packages Products Rev 1.20 13 November 6, 2013 HT7936A/HT7936B 6-pin SOT23-6 Outline Dimensions D C H E q e A A 2 b Symbol A A 1 Dimensions in inch Min. Nom. Max. ¾ ¾ 0.057 A1 ¾ ¾ 0.006 A2 0.035 0.045 0.051 b 0.012 ¾ 0.020 C 0.003 ¾ 0.009 D ¾ 0.114 BSC ¾ E ¾ 0.063 BSC ¾ e ¾ 0.037 BSC ¾ E1 ¾ 0.075 BSC ¾ H ¾ 0.110 BSC ¾ L 0.012 0.018 0.024 q 0° ¾ 8° Symbol A Rev 1.20 L Dimensions in mm Min. Nom. Max. ¾ ¾ 1.45 0.15 A1 ¾ ¾ A2 0.90 1.15 1.30 b 0.30 ¾ 0.50 C 0.08 ¾ 0.22 D ¾ 2.90 BSC ¾ E ¾ 1.60 BSC ¾ e ¾ 0.95 BSC ¾ e1 ¾ 1.90 BSC ¾ H ¾ 2.80 BSC ¾ L 0.30 0.45 0.60 q 0° ¾ 8° 14 November 6, 2013 HT7936A/HT7936B Copyright Ó 2013 by HOLTEK SEMICONDUCTOR INC. The information appearing in this Data Sheet is believed to be accurate at the time of publication. However, Holtek assumes no responsibility arising from the use of the specifications described. The applications mentioned herein are used solely for the purpose of illustration and Holtek makes no warranty or representation that such applications will be suitable without further modification, nor recommends the use of its products for application that may present a risk to human life due to malfunction or otherwise. Holtek¢s products are not authorized for use as critical components in life support devices or systems. Holtek reserves the right to alter its products without prior notification. For the most up-to-date information, please visit our web site at http://www.holtek.com.tw. Rev 1.20 15 November 6, 2013