RT9919 7 Channel DC/DC Converters General Description Features The RT9919 is a complete power supply solution for digital still cameras and other hand held devices. The RT9919 is a multi-channel DC/DC converter including two step-up DC/DC converters, two step-down DC/DC converters, one selectable step-up/step-down DC/DC converter, one inverting DC/DC converter and one WLED driver. l l l l l l The RT9919 is designed to fulfill the applications for DSC just as follows : l CH1 is a synchronous step-up output for motor or DSC system I/O power CH2 is a selectable synchronous step-up/step-down output for motor or DSC system I/O power CH3 and CH4 are synchronous step-down outputs for DSP core and memory power supply l l l l l CH5 is a high voltage step-up output for CCD bias power supply CH6 is an inverting output for negative CCD bias power supply CH7 is a high voltage step-up output for driving WLED l l 1 Channel Syn Boost/Buck Selectable 2AA/Li Application Topologies Set by SEL Pin Preset On/Off Sequence 5 Channels with Internal Compensation All Power Switches Integrated Syn Step-Down DC/DC Converter : } Up to 95% Efficiency } 100% (max) Duty Cycle Syn Step-Up DC/DC Converter : } Adjustable Output Voltage } Up to 95% Efficiency Open LED Protection Transformerless Inverting Converter for CCD Fixed 2MHz Switching Frequency at CH1 to CH4 Fixed 1MHz Switching Frequency at CH5 to CH7 RTC_LDO/SW1 Selectable by CN Pin 40-Lead WQFN Package RoHS Compliant and Halogen Free Applications Digital Still Camera PDA Portable Device l For the selectable step-up/step-down converter, the Boost/ Buck can be selected by the SEL pin. Among all channels, there are 5 channels with the built -in i nternal com pensation. The RT9919 al so prov ides a l transformerless inverting converter for supplying the CCD power. For the synchronous step-up and step down RT9919 l Ordering Information Package Type QW : WQFN-40L 5x5 (W-Type) Lead Plating System G : Green (Halogen Free and Pb Free) converters, the efficiency can be up to 95%. The IC provides load disconnection for channel 1 and channel 5. The IC has selectable RTC_LDO/SW1 that can be determined by the CN pin. Note : Richtek products are : The RT9919 is able to support Li+ and 2AA battery applications. The RT9919 provides WLED open protection, current limit, thermal shutdown protection, over voltage and under voltage protection to achieve complete protection. The RT9919 is available in WQFN-40L 5x5 package. DS9919-01 April 2011 } RoHS compliant and compatible with the current requirements of IPC/JEDEC J-STD-020. } Suitable for use in SnPb or Pb-free soldering processes. www.richtek.com 1 RT9919 Pin Configurations EN1234 LX2 COMP2 COMP1 FB1 OK VOUT1 FB2 LX1 SYS_R (TOP VIEW) 40 39 38 37 36 35 34 33 32 31 PVDD1 LX6 PVDD6 CP CN PNEG FB6 FB4 EN6 LX4 1 30 2 29 3 28 4 27 5 26 GND 6 25 7 24 8 23 41 9 22 21 10 PVDD2 VDDM CFB7 GND LX7 LX5 VOUT7 FB3 EN7 LX3 RTC_PWR PVDD3 SEL RTC_R FB5 VREF SW5O SW5I EN5 PVDD4 11 12 13 14 15 16 17 18 19 20 WQFN-40L 5x5 www.richtek.com 2 DS9919-01 April 2011 RT9919 Typical Application Circuit For 2AA 3.3V VBAT C23 1uF L1 1.2uH VBAT VOUT_CH1 3.3V 40 LX1 Q1 C1 10uF 1 R19 50k 37 C3 R3 560pF 40k R2 150k L2 1.2uH VBAT PVDD1 RT9919 38 COMP1 36 OK 35 VOUT1 3.3V L3 2.2uH VOUT_CH3 2.5V R7 76.8k C9 10uF LX6 2 33 R12 90.9k VBAT C25 1uF VOUT_CH6 -7V D4 VREF 16 VBAT C26 1uF 21 LX3 LX7 23 FB3 C19 0.1uF L7 10uH 20 PVDD3 C10 220pF C18 10uF/16V x 2 C17 1nF FB6 7 R14 11.3k COMP2 R8 36k 26 WLED D5 D1 VOUT7 24 C20 1uF/16V D2 CFB7 28 3.3V VOUT_CH4 1.8V C11 10uF C12 10uF R11 1000k L6 10uH PVDD2 34 FB2 C7 R6 560pF 40k VOUT_CH5 15V C16 10uF/25V 15V C15 1nF R13 63.4k R4 470k R5 88.7k C8 10uF FB5 15 PVDD6 3 31 LX2 30 C14 10uF/25V FB1 C4 10uF VOUT_CH2 5V D3 SW5O 13 SW5I 14 C27 10uF x 2 C2 4.7pF R1 470k C5 10uFx2 LX5 25 C22 10uF C24 1uF L5 10uH 29 VDDM L4 2.2uH 11 PVDD4 RTC_R 10 LX4 C13 33pF R9 470k RTC_PWR 8 R10 374k ON OFF 18 32 12 9 17 FB4 EN1234 EN5 EN6 SEL 22 EN7 27, Exposed Pad (41) SYS_R R15 10 R16 10k RTC 3.05V 39 SYS Reset R17 100k CP 4 CN 5 PNEG GND 19 RTC Reset 3.3V C28 0.1uF 6 C29 1uF Note : (1) SEL = High, CH2 is Boost, CN Connect to CAP (2) VBAT = 1.8V to 3.2V Timing Diagram Power On Sequence : CH1 Boost 3.3V→ CH3 Buck 2.5V→ CH4 Buck 1.8V→ (CH2 Boost 5V and SW1 3.3V) Power Off Sequence : (CH2 Boost 5V and SW1 3.3V)→ CH4 Buck 1.8V → CH3 Buck 2.5V → CH1 Boost 3.3V VDDM EN1234 CH1 V OUT 3.3V CH3 V OUT 2.5V CH4 V OUT 1.8V V OUT1 3.3V CH2 V OUT 5V DS9919-01 April 2011 User define 3.5ms 3.5ms 3.5ms 3.5ms 3.5ms IC shutdown Wait until FB3 < 0.1V Wait until FB4 < 0.1V Wait until V OUT1 < 0.4V Depends on loading www.richtek.com 3 RT9919 For Li-ion 5V L1 1.2uH VBAT 40 LX1 LX5 25 1 PVDD1 C1 10uF x 2 R1 470k C3 560pF R2 88.7k R3 40k VBAT RTC 3.05V C21 0.22uF VBAT or 5V L2 1uH 36 OK 35 VOUT1 C7 R6 2200pF 15k R5 150k VBAT C8 10uF L3 2.2uH VOUT_CH3 2.5V C9 10uF PVDD2 34 FB2 33 COMP2 PVDD6 3 LX6 2 C25 1uF 23 FB3 R12 90.9k L6 10uH D4 R13 63.4k R14 11.3k VREF 16 C17 1nF VOUT_CH6 -7V C18 10uF/16V x 2 C19 0.1uF L7 10uH VBAT C26 1uF LX7 VOUT_CH5 15V R11 1000k VBAT FB6 7 21 LX3 R8 36k 26 WLED D5 D1 VOUT7 24 D2 C20 1uF/16V CFB7 28 VBAT VOUT_CH4 1.8V C11 10uF C12 10uF FB5 15 20 PVDD3 C10 220pF R7 76.8k RT9919 C16 10uF/25V 15V C15 1nF 31 LX2 C6 10pF R4 470k C14 10uF/25V FB1 38 COMP1 30 VOUT_CH2 3.3V C4 10uF C5 10uF D3 SW5O 13 SW5I 14 C2 4.7pF 37 C24 1uF L5 10uH 29 VDDM C22 10uF VOUT_CH1 5V VBAT C23 1uF L4 2.2uH 11 PVDD4 10 LX4 C13 33pF R9 470k 8 R10 374k ON OFF 32 12 9 17 18 RTC_PWR 19 SYS_R EN1234 EN5 EN6 SEL RTC Reset R15 10 R16 10k RTC 3.05V 39 FB4 22 EN7 27, Exposed Pad (41) RTC_R SYS Reset R17 100k CP 4 CN PNEG 5 3.3V R18 10k VBAT 6 GND Note : (1) SEL = Low, CH2 is Buck, CN Pull High (2) VBAT = 2.7V to 4.2V Timing Diagram Power On Sequence : CH1 Boost 5V →CH3 Buck 2.5V→ CH4 Buck 1.8V→ CH2 Buck 3.3V Power Off Sequence : CH2 Buck 3.3V→ CH4 Buck 1.8V→ CH3 Buck 2.5V→ CH1 Boost 5V VDDM EN1234 CH1 V OUT 5V CH3 V OUT 2.5V CH4 V OUT 1.8V CH2 V OUT 3.3V www.richtek.com 4 User define 3.5ms 3.5ms 3.5ms 3.5ms IC shutdown Wait until FB3 < 0.1V Wait until FB4 < 0.1V Wait until FB2 < 0.1V DS9919-01 April 2011 RT9919 Table 1 Channel CH3 Formula V OUT = (1+R7/R8) x 0.8 VOUT (V) 2.5 1.8 1.5 1.3 1.2 1.0 L3 (uH) 2.2 2.2 2.2 2.2 2.2 2.2 R7 (kΩ) 768 470 330 237 187 23.2 R 8 (kΩ) 360 374 374 374 374 93.1 C10 (pF) 22 33 47 68 82 47 COUT (uF) 10 10 10 10 10 10 Channel CH 4 Application V OUT = (1+R9/R10) x 0.8 V OUT (V) 2.5 1.8 1.5 1.3 1.2 1.0 L4 (uH) 2.2 2.2 2.2 2.2 2.2 2.2 R9 (kΩ) 768 470 330 237 187 23.2 R 10 (kΩ) 360 374 374 374 374 93.1 C13 (pF) 22 33 47 68 82 47 COUT (uF) 10 10 10 10 10 10 Channel CH5 Formula VO UT = (1+R11/R12) x 1.25 VOUT (V) 12 13 14 15 15.5 16 L5 (uH) 10 10 10 10 10 10 R11 (kΩ) 820 820 953 1000 820 887 R12 (kΩ) 95.3 86.6 93.1 90.9 71.5 75 C15 (pF) 1000 1000 1000 1000 1000 1000 C OUT (uF) 10/16V 10/16V 10/25V 10/25V 10/25V 10/25V Channel CH6 Form ula V OUT = (R 13/R14) x (-1.25) * R13+R14 <90k V OUT (V) -6 -6.3 -7 -7.5 -8 L6 (uH) 10 10 10 10 10 R13 (kΩ) 57.6 69.8 63.4 68 68 R14 (kΩ) 12 13.7 11.3 11.3 10.5 C17 (pF) 1000 1000 1000 1000 1000 COUT (uF) 10 x 2pcs 10 x 2pcs 10 x 2pcs 10 x 2pcs 10 x 2pcs DS9919-01 April 2011 www.richtek.com 5 RT9919 Functional Pin Description Pin No. Pin Name Pin Function 1 PVDD1 Power Input pin of CH1. 2 3 LX6 PVDD6 Switch Node of CH6. High impedance in shutdown. Power Input Pin of CH6. 4 5 CP CN Charge Pump External Driver Pin. Charge Pump External Driver Pin. 6 PNEG Negative Output Pin of Charge Pump. 7 FB6 Feedback Input Pin of CH6. High impedance in shutdown. 8 FB4 Feedback Input Pin of CH4. High impedance in shutdown. 9 EN6 Enable Pin of CH6. 10 LX4 Switch Node of CH4. High impedance in shutdown. 11 PVDD4 Power Input Pin of CH4. 12 13 EN5 SW5O Enable Pin of CH5. Output Pin of CH5 Load Disconnect. 14 15 SW5I FB5 Input Pin of CH5 Load Disconnect. Feedback Input Pin of CH5. High impedance in shutdown. 16 VREF 1.25V Reference Output Pin. 17 SEL Li or 2AA Select Pin. Logic state can not be changed during operation. 18 RTC_R RTC Reset Output Pin. 19 RTC_PWR Power Input Pin of RTC-Reset. 20 PVDD3 Power Input Pin of CH3 21 LX3 Switch Node of CH3. High impedance in shutdown. 22 EN7 Enable Pin of CH7. 23 FB3 Feedback Input Pin of CH3. High impedance in shutdown. 24 VOUT7 Sense Pin for CH7 Output Voltage. 25 LX5 Switch Node of CH5. High impedance in shutdown. 26 LX7 27, GND 41 (Exposed Pad) 28 CFB7 Switch Node of CH7. High impedance in shutdown. Ground Pin. The exposed pad must be soldered to a large PCB and connected to GND for maximum thermal dissipation. Feedback Input Pin of CH7. 29 VDDM IC analog Input Power Pin. 30 31 PVDD2 LX2 Power Input Pin of CH2. Switch Node of CH2. High impedance in shutdown. 32 EN1234 Enable Pin of CH1, CH2, CH3 and CH4. 33 34 COMP2 FB2 Compensation Pin of CH2. Feedback input pin of CH2. High impedance in shutdown. 35 VOUT1 Sense Pin for CH1 Output Voltage. High impedance in shutdown. 36 OK External Switch Control Pin. High impedance in shutdown. 37 FB1 Feedback Input Pin of CH1. High impedance in shutdown. 38 COMP1 Compensation Pin of CH1. Pull to GND in shutdown. 39 SYS_R System Reset Output Pin. 40 LX1 Switch Node of CH1. High impedance in shutdown. www.richtek.com 6 DS9919-01 April 2011 RT9919 Function Block Diagram VDDM PVDD1 LX5 CH5 C-Mode Step-Up PWM CH1 C-Mode Step-Up LX1 + FB5 1.25V REF SW5 SW5I SW5O COMP1 FB1 + 0.8V REF PVDD6 PVDD2 CH6 C-Mode Inverting CH2 C-Mode Step-Up or Step-Down LX6 FB6 + - LX7 0.8V REF PVDD3 + CFB7 VDDM 0.25V REF VREF CH3 C-Mode Step-Down Enable Mode Sequence 1.25V REF EN1234 EN5 EN6 SEL LX3 PVDD3 + CP CN PNEG OK VOUT1 COMP2 FB2 + CH7 C-Mode Step-Up PWM VOUT7 EN7 LX2 FB3 0.8V REF Negative Charge Pump PVDD4 RTC LDO SW1 CH4 C-Mode Step-Down RTC_PWR RTC_R LX4 PVDD4 RTC Reset CN = High, select FB2 CN = Other, select VOUT1 SYS_R System Reset Select VOUT1 FB2 + FB4 0.8V REF FB3 GND Timing Diagram CH5 and CH6 Timing Diagram EN5 10ms SW5I Depends on loading SW5O (to CCD +) Depends on loading EN6 CH6 V OUT DS9919-01 April 2011 10ms Depends on loading www.richtek.com 7 RT9919 Absolute Maximum Ratings (Note 1) Supply Voltage, VDDM ------------------------------------------------------------------------------ 0.3V to 7V Power Switch : LX1, LX2, LX4 ---------------------------------------------------------------------------------------- −0.3V to 6.5V LX5, LX7, SW5I, SW5O, VOUT7 ---------------------------------------------------------------- −0.3V to 21V LX6 ----------------------------------------------------------------------------------------------------- (PVDD6 − 14V) to (PVDD6 + 0.3V) l The Other Pins -------------------------------------------------------------------------------------- −0.3V to 6.5V l Power Dissipation, PD @ TA = 25°C WQFN 40L 5x5 -------------------------------------------------------------------------------------- 2.778W l Package Thermal Resistance (Note 2) WQFN 40L 5x5, θJA --------------------------------------------------------------------------------- 36°C/W WQFN 40L 5x5, θJC -------------------------------------------------------------------------------- 7°C/W l Junction Temperature ------------------------------------------------------------------------------ 150°C l Lead Temperature (Soldering, 10 sec.) --------------------------------------------------------- 260°C l Storage Temperature Range ---------------------------------------------------------------------- −65°C to 150°C l ESD Susceptibility (Note 3) HBM (Human Body Mode) ------------------------------------------------------------------------ 2kV MM (Machine Mode) ------------------------------------------------------------------------------- 200V l l Recommended Operating Conditions l l (Note 4) Junction Temperature Range --------------------------------------------------------------------- −40°C to 125°C Ambient Temperature Range --------------------------------------------------------------------- −40°C to 85°C Electrical Characteristics (VDDM = 3.3V, TA = 25°C, unless otherwise specified) Parameter Symbol T est Condition Min Typ Max Units Supply Voltage VDDM Operating Voltage V DDM 2.7 -- 5.5 V VDDM Minimum Startup Voltage VDDM Over Voltage Protection V ST 1.5 5.6 -6 -6.5 V V Supply Current Shutdown Supply Current into VDDM CH1 (Syn-Boost) : Supply Current into VDDM CH2 (Syn-Boost or Syn-Buck) : Supply Current into VD DM CH3 (Syn-Buck) : Supply Current into VDDM CH4 (Syn-Buck) : Supply Current into VDDM CH5 (Asyn-Boost) : Supply Current into VDDM CH6 (Inverting) + Charge pump : Supply Current into VDDM CH7 (WLED): Supply Current into VDDM I OFF All EN = 0, CN = 3.3V -- 1 10 uA I Q1 Non Switching, EN1234 = 3.3V -- -- 800 uA I Q2 Non Switching, EN1234 = 3.3V -- -- 800 uA I Q3 Non Switching, EN1234 = 3.3V -- -- 800 uA I Q4 Non Switching, EN1234 = 3.3V -- -- 800 uA I Q5 Non Switching, EN5 = 3.3V -- -- 800 uA IQ6 Non Switching, EN6 = 3.3V PVDD 6 = 3.3V -- -- 800 uA IQ7 Non Switching, EN7 = 3.3V -- -- 800 uA To be continued www.richtek.com 8 DS9919-01 April 2011 RT9919 Parameter Oscillator CH1,2,3,4 Operating Frequency CH5, 6, 7 Operating Frequency Symbol Test Condition f OSC f OSC2 Min Typ Max Units 1800 900 2000 1000 2200 1100 kHz kHz CH1 Maximum Duty Cycle (Boost) CH2 Maximum Duty Cycle (Boost) VFB1 = 0.7V VFB2 = 0.7V 80 80 83 83 86 86 % % CH2 Maximum Duty Cycle (Buck) CH3 Maximum Duty Cycle (Buck) CH4 Maximum Duty Cycle (Buck) VFB2 = 0.7V VFB3 = 0.7V VFB4 = 0.7V ---- ---- 100 100 100 % % % CH5 Maximum Duty Cycle (Boost) CH6 Maximum Duty Cycle (Inverting) CH7 Maximum Duty Cycle (WLED) VFB5 = 1.15V VFB6 = 0.1V CFB 7 = 0.15V 91 91 91 94 94 94 97 97 97 % % % 0.788 0.8 0.812 V 1.237 1.25 1.263 V -15 0 15 mV 0.237 0.25 0.263 V 60 -- -- uA 1.237 1.25 1.263 V -- -- 10 mV 3.9 3.4 4.1 4 3.6 4.5 4.2 3.8 4.9 V V V P-MOSFET, PVDD 1 = 3.3V -- 150 -- mΩ N-MOSFET, PVDD1 = 3.3V -- 150 -- mΩ Feedback Regulation Voltage Feedback Regulation Voltage @ FB1, FB2, FB3, FB4 Feedback Regulation Voltage @ FB5 Feedback Regulation Voltage @ FB6 (Inverting) Feedback Regulation Voltage @ CFB7 OK Sink Current Reference VREF Output Voltage OK = 1V V REF VREF Load Regulation Negative Charge Pump 0uA < IREF < 200uA PVDD6 High Threshold to Stop Pump PVDD6 Low Threshold to Stop Pump (PVDD6 − PNEG) Clamped Voltage PVDD6 = 3.3V Power Switch CH1 On Resistance of MOSFET RDS(ON) CH1 Current Limitation (Boost) CH2 On Resistance of MOSFET RDS(ON) -- 3 -- A P-MOSFET, PVDD 2 = 3.3V -- 150 -- mΩ N-MOSFET, PVDD2 = 3.3V -- 150 -- mΩ -- 1.5 -- A CH2 Current Limitation (Buck) CH2 Current Limitation (Boost) CH3 On Resistance of MOSFET R DS(ON) -- 3 -- A P-MOSFET, PVDD 3 = 3.3V -- 200 -- mΩ N-MOSFET, PVDD3 = 3.3V -- 200 -- mΩ P-MOSFET, PVDD 4 = 3.3V --- 1.5 200 --- A mΩ N-MOSFET, PVDD4 = 3.3V -- 200 -- mΩ -- 1.5 -- A CH3 Current Limitation (Buck) CH4 On Resistance of MOSFET R DS(ON) CH4 Current Limitation (Buck) CH5 Load Disconnect MOSFET P-MOSFET , SW5I = 3.3V -- 0.5 -- Ω CH5 On Resistance of MOSFET N-MOSFET -- 0.5 -- Ω CH5 Current Limitation N-MOSFET -- 1.2 -- A To be continued DS9919-01 April 2011 www.richtek.com 9 RT9919 Parameter Symbol Test Condition Min Typ Max Units CH6 On Resistance of MOSFET P-MOSFET, PVDD6 = 3.3V -- 1 -- Ω CH6 Current Limitation P-MOSFET -- 1.5 -- A CH7 On Resistance of MOSFET N-MOSFET -- 0.5 -- Ω CH7 Current Limitation N-MOSFET -- 0.8 -- A 5.5 6 6.5 V -- -- 0.6 V Under Voltage Protection of VOUT1 -- 1.75 -- V Over Voltage Protection of SW5I 18 -- 21 V Over Voltage Protection of VOUT7 12 -- 16 V 0.35 0.4 0.45 V Under Voltage Protection of FB2 -- 0.4 -- V Under Voltage Protection of FB3 -- 0.4 -- V Under Voltage Protection of FB4 -- 0.4 -- V Protection Fault Delay -- 100 -- ms 1.3 -- -- V -- -- 0.4 V -- 2 6 uA Protection Over Voltage Protection of PVD D1 and PVDD2 Over Voltage Protection Hysteresis of PVDD1 and PVDD2 CH5 Load Disconnect UVP of SW5O Control EN1234, EN5, EN6, EN7 Input High Level Threshold EN1234, EN5, EN6, EN7 Input Low Level Threshold EN1234, EN5, EN6, EN7 Sink Current SEL Input H igh Level Threshold 1.3 -- -- V SEL Input Low Level Threshold -- -- 0.4 V SEL Sink C urrent SEL = 3.3V -- 3 9 uA SEL Sink C urrent All EN = 0 -- 0 -- uA 125 160 -- °C -- 20 -- °C 0.709 0.72 0.731 V Thermal Protection Thermal Shutdown TS D Thermal Shutdown Hysteresis ΔTSD System Reset FB2 Regulation Threshold CN = 3.3V Hysteresis -- 40 -- mV 0.709 0.72 0.731 V -- 40 -- mV 2.95 3.0 3.05 V Hysteresis -- 0.15 -- V SYS_R Rising Delay Time -- 10 -- ms 4 -- -- mA FB3 Regulation Threshold Hysteresis VOUT1 Regulation Threshold SYS_R Sink Capability SYS_R = 0.5V To be continued www.richtek.com 10 DS9919-01 April 2011 RT9919 Parameter Symbol Test Condition Min Typ Max Units 1.57 1.6 1.63 V --- 16 2 -4 mV uA 35 55 75 ms 4 -- -- mA VIN = 4.2V --- -5 5.5 8 V uA IOUT = 0mA -- 3.05 -- V VIN = 4.2V 60 -- -- mA IOUT = 20mA -- -- 200 mV RTC Reset RTC_PWR Reset Threshold Hysteresis Standby Current RTC_PWR = 3V RTC_R Rising Delay Time RTC_R = 0.5V, RTC_PWR = 1.6V RTC_R Sink Capability RTC LDO, CN = High Input Voltage Range Standby Current VIN Output Voltage VOUT Maximum Output Current Dropout Voltage VDROP Note 1. Stresses listed as the above “ Absolute Maximum Ratings” may cause permanent damage to the device. These are for stress ratings. Functional operation of the device at these or any other conditions beyond those indicated in the operational sections of the specifications is not implied. Exposure to absolute maximum rating conditions for extended periods may remain possibility to affect device reliability. Note 2. θJA is measured in the natural convection at TA = 25°C on a high effective four layers thermal conductivity test board of JEDEC 51-7 thermal measurement standard. The case point of θJC is on the expose pad for the package. Note 3. Devices are ESD sensitive. Handling precaution is recommended. Note 4. The device is not guaranteed to function outside its operating conditions. DS9919-01 April 2011 www.richtek.com 11 RT9919 Typical Operating Characteristics CH1 Boost Efficiency vs. Output Current CH1 Boost Efficiency vs. Output Current 100 100 90 90 80 VBAT VBAT VBAT VBAT VBAT VBAT 70 60 50 40 = = = = = = 3V 2.7V 2.5V 2.2V 2V 1.8V 30 Efficiency (%) Efficiency (%) 80 VBAT VBAT VBAT VBAT VBAT VBAT 70 60 50 40 = = = = = = 4.5V 4.2V 3.9V 3.6V 3.3V 3V 30 20 20 10 10 VOUT = 3.3V, L = 1.2uH, COUT = 10uF x 2 VOUT = 5V, L = 1.2uH, COUT = 10uF x 2 0 0 10 100 10 1000 100 CH2 Buck Efficiency vs. Output Current 100 90 90 80 80 VBAT VBAT VBAT VBAT VBAT VBAT VBAT 60 50 40 30 = = = = = = = 3.3V 3V 2.7V 2.5V 2.2V 2V 1.8V Efficiency (%) Efficiency (%) CH2 Boost Efficiency vs. Output Current 100 70 VBAT VBAT VBAT VBAT VBAT 70 60 50 = = = = = 3.4V 3.6V 3.9V 4.2V 4.5V 40 30 20 20 10 10 VOUT = 3.3V, L = 1uH, COUT = 10uF VOUT = 5V, L = 1.2uH, COUT = 10uF x 2 0 0 10 100 10 1000 100 1000 Output Current (mA) Output Current (mA) CH3 Buck Efficiency vs. Output Current CH4 Buck Efficiency vs. Output Current 100 100 90 90 80 80 VBAT VBAT VBAT VBAT VBAT VBAT VBAT 70 60 50 40 = = = = = = = 2.7V 3V 3.3V 3.6V 3.9V 4.2V 4.5V Efficiency (%) Efficiency (%) 1000 Output Current (mA) Output Current (mA) 30 70 VBAT VBAT VBAT VBAT VBAT VBAT VBAT 60 50 40 30 = = = = = = = 1.8V 2.5V 3V 3.3V 3.6V 4.2V 4.5V 20 20 10 VOUT = 2.5V, L = 2.2uH, COUT = 10uF 10 VOUT = 1V, L = 2.2uH, COUT = 10uF 0 0 10 100 Output Current (mA) www.richtek.com 12 1000 10 100 1000 Output Current (mA) DS9919-01 April 2011 RT9919 CH6 Inverting Efficiency vs. Output Current CH5 Boost Efficiency vs. Output Current 100 100 90 90 Efficiency (%) 80 70 60 = = = = = 4.5V 4.2V 3.9V 3.6V 3.4V 50 40 30 80 Efficiency (%) VBAT VBAT VBAT VBAT VBAT VBAT VBAT VBAT VBAT VBAT 70 60 4.5V 4.2V 3.9V 3.6V 3.4V 50 40 30 20 20 10 10 VOUT = 16V, L = 10uH, COUT = 10uF VOUT = −8V, L = 10uH, COUT = 10uF x 2 0 0 1 10 1 100 10 100 Output Current (mA) Output Current (mA) CH7 Efficiency vs. Input Voltage CH1 Boost Output Voltage vs. Output Current 100 5.10 90 5.09 80 5.08 Output Voltage (V) Efficiency (%) = = = = = 70 60 50 40 30 5.07 5.06 5.05 5.04 5.03 5.02 20 10 IOUT = 25mA, L = 10uH, COUT = 1uF 5.01 VBAT = 3V, VOUT = 5V 5.00 0 3.4 3.5 3.6 3.7 3.8 3.9 4 0 4.1 4.2 4.3 4.4 4.5 100 Input Voltage (V) 200 300 400 500 600 Output Current (mA) CH2 Buck Output Voltage vs. Output Current CH3 Buck Output Voltage vs. Output Current 2.7 3.50 3.45 2.6 Output Voltage (V) Output Voltage (V) 3.40 3.35 3.30 3.25 3.20 3.15 2.5 2.4 2.3 2.2 3.10 2.1 3.05 VBAT = 4.5V, VOUT = 3.3V 3.00 VBAT = 3V, VOUT = 2.5V 2 0 100 200 300 400 Output Current (mA) DS9919-01 April 2011 500 600 0 100 200 300 400 500 600 Output Current (mA) www.richtek.com 13 RT9919 CH5 Boost Output Voltage vs. Output Current CH4 Buck Output Voltage vs. Output Current 16.50 1.10 16.45 1.05 Output Voltage (V) Output Voltage (V) 16.40 1.00 0.95 0.90 0.85 0.80 16.35 16.30 16.25 16.20 16.15 16.10 0.75 16.05 VBAT = 3.4V, VOUT = 16V VBAT = 3V, VOUT = 1V 0.70 16.00 0 100 200 300 400 500 600 0 Output Current (mA) 10 20 30 40 50 60 70 80 90 100 Output Current (mA) CH6 Inverting Output Voltage vs. Output Current CH1, CH2, CH3 and CH4 Power On Output Voltage (V) -8.00 -8.05 VOUT_CH1 (5V/Div) -8.10 VOUT_CH2 (2V/Div) -8.15 VOUT_CH3 (2V/Div) -8.20 VOUT_CH4 (1V/Div) -8.25 VBAT = 3.4V, VOUT = −8V -8.30 0 10 20 30 40 50 60 70 80 90 VBAT = 3.6V, SEL = Low 100 Time (5ms/Div) Output Current (mA) CH1, CH2, CH3 and CH4 Power Off CH1, CH2, CH3 and CH4 Power On VOUT_CH1 (5V/Div) VOUT_CH1 (5V/Div) VOUT_CH2 (5V/Div) VOUT_CH2 (5V/Div) VOUT_CH3 (2V/Div) VOUT_CH3 (2V/Div) VOUT_CH4 (1V/Div) VOUT_CH4 (1V/Div) VBAT = 3.6V, SEL = Low Time (2.5ms/Div) www.richtek.com 14 VOUT_SW1 (2V/Div) VBAT = 3V, SEL = High Time (2.5ms/Div) DS9919-01 April 2011 RT9919 CH1 Output Voltage Ripple CH1, CH2, CH3 and CH4 Power Off VOUT_CH1 (5V/Div) VOUT_CH2 (5V/Div) VOUT_CH3 (2V/Div) LX1 (2V/Div) VOUT_CH4 (1V/Div) VOUT_ac (10mV/Div) VOUT_SW1 (2V/Div) VBAT = 3.6V, VOUT = 5V, IOUT = 300mA, L = 1.2uH, COUT = 10uF x 2 VBAT = 3V, SEL = High Time (2.5ms/Div) Time (250ns/Div) CH2 Output Voltage Ripple CH3 Output Voltage Ripple LX2 (2V/Div) LX3 (2V/Div) VOUT_ac (5mV/Div) VOUT_ac (5mV/Div) VBAT = 3.6V, VOUT = 2.5V, IOUT = 300mA, L = 2.2uH, COUT = 10uF VBAT = 4.2V, VOUT = 3.3V, IOUT = 300mA, L = 1uH, COUT = 10uF Time (250ns/Div) Time (250ns/Div) CH4 Output Voltage Ripple CH5 Output Voltage Ripple LX4 (2V/Div) LX5 (5V/Div) VOUT_ac (5mV/Div) VOUT_ac (10mV/Div) VBAT = 3.6V, VOUT = 1V, IOUT = 300mA, L = 2.2uH, COUT = 10uF Time (250ns/Div) DS9919-01 April 2011 VBAT = 3.6V, VOUT = 16V, IOUT = 30mA, L = 10uH, COUT = 10uF Time (250ns/Div) www.richtek.com 15 RT9919 CH6 Output Voltage Ripple CH7 Output Voltage Ripple LX6 (5V/Div) LX7 (5V/Div) VOUT_ac (5mV/Div) VOUT_ac (20mV/Div) VBAT = 3.6V, VOUT = −8V, IOUT = 30mA, L = 10uH, COUT = 10uF x 2 VBAT = 3V, VOUT = 10V, IOUT = 3LEDs, L = 10uH, COUT = 1uF Time (250ns/Div) Time (250ns/Div) CH1 Load Transient Response CH3 Load Transient Response VBAT = 3.7V, VOUT = 2.5V, IOUT = 50mA to 300mA, L = 2.2uH, COUT = 10uF VBAT = 3.7V, VOUT = 5V, IOUT = 50mA to 300mA, L = 1.2uH, COUT = 10uF x 2 I LOAD (200mA/Div) I LOAD (200mA/Div) VOUT_ac (50mV/Div) VOUT_ac (50mV/Div) Time (1ms/Div) Time (1ms/Div) CH5 Load Transient Response CH6 Load Transient Response I LOAD (20mA/Div) I LOAD (20mA/Div) VOUT_ac (50mV/Div) VOUT_ac (50mV/Div) VBAT = 3.7V, VOUT = 16V, IOUT = 10mA to 30mA, L = 10uH, COUT = 10uF Time (1ms/Div) www.richtek.com 16 VBAT = 3.7V, VOUT = −8V, IOUT = 15mA to 50mA, L = 10uH, COUT = 10uF x 2 Time (1ms/Div) DS9919-01 April 2011 RT9919 Application information The RT9919 includes the following seven DC/DC converter channels to build a multiple-output power-supply system. CH1 : Step-up synchronous current mode DC/DC converter with internal power MOSFETs. The output voltage could be load disconnected by a switch controller and an external P-MOSFET. CH2 : Selectable Step-Up or Step-Down Converter Step-up : The converter operates at fixed frequency PWM mode, continuous current mode (CCM), and discontinuous current mode (DCM) with internal MOSFET and synchronous rectifier for up to 95% efficiency. CH2 : Selectable step-up or step-down synchronous current mode DC/DC converter with internal power MOSFETs. Step-down : The converter operates at fixed frequency PWM mode and continuous current mode (CCM) with internal MOSFET and synchronous rectifier for up to 95% efficiency. CH3 : Step-down synchronous current mode DC/DC converter with internal power MOSFETs and internal compensation network. While the input voltage is close to the output voltage, the converter enters low dropout mode. The duty could be as long as 100% to extend battery life. CH4 : Step-down synchronous current mode DC/DC converter with internal power MOSFETs and internal compensation network. CH5 : Step-up asynchronous current mode DC/DC converter with internal power MOSFET and internal compensation network. The output voltage could be load disconnected by an internal P-MOSFET. CH6 : Inverting current mode DC/DC converter with internal power MOSFET and internal compensation network. CH7 : Current mode WLED driver with internal power MOSFET and internal compensation network. This channel also provides open LED protection. CH3 : Step-Down DC/DC Converter The converter operates at fixed frequency PWM mode, CCM and integrated internal compensation. While the input voltage is close to the output voltage, the converter could enter low dropout mode with low output ripple. The duty could be as long as 100% to extend battery life. CH4 : Step-Down DC/DC Converter The converter operates at fixed frequency PWM mode, CCM and integrated internal compensation. While the input voltage is close to the output voltage, the converter could enter low dropout mode with low output ripple. The duty could be as long as 100% to extend battery life. SW1 : Load disconnect controller. SW5 : Load disconnect switch for CH5 CH1 to CH4 operate in PWM mode with 2MHz and CH5 to CH7 operate in PWM mode with 1MHz constant frequency under moderate to heavy loading. RTC_LDO : Low quiescent current, high output voltage accuracy LDO for Real Time Clock. RTC_Reset : Accurate voltage detector for RTC LDO. System_Reset : Accurate voltage detector for power sequence. CH1 : Step-Up Converter Step-up : The converter operates at fixed frequency PWM mode, continuous current mode (CCM), and discontinuous current mode (DCM) with internal MOSFET and synchronous rectifier for up to 95% efficiency. DS9919-01 April 2011 CH5 : Step-Up DC/DC Converter It integrates asynchronous boost with an internal MOSFET, internal compensation and an external schottky diode to provide CCD positive power supply. The converter is inactive until the SW5 soft start procedure is finished. This feature provides load disconnect function and effectively limits inrush current at start up. CH6 : INV DC/DC Controller This controller integrates an internal P-MOSFET and an external schottky diode to provide CCD negative power supply. The output voltage is set as VOUT = (R13/R14) x (−VREF) where R13 and R14 are the feedback resisters connected to FB6, VREF equals to 1.25V in typical. www.richtek.com 17 RT9919 CH7 : WLED Driver RTC LDO It is an asynchronous DC/DC converter with an internal MOSFET, internal compensation and an external schottky diode to drive up to 3 WLED. This channel also features PWM dimming control from EN7 pin and open diode protection. The current through WLED is set as The RT9919 provides a LDO for real time clock. LDO function has features of low quiescent current (5uA) and high output voltage accuracy since this LDO is running all the time, even when the system is shutdown. In addition, LDO share “OK” and “VOUT1” pin with SW1 and function is decided by “CN” pin. Following table is used to select LDO or SW1. I (mA) = [250mV/R(Ω)] x Duty (%) R : Current sense resistor from CFB7 to GND. Table1. RTC LDO Setting Duty: PWM dimming by EN7 pin. Dimming frequency range is from 30kHz to 100kHz. Hold EN7 low for more than 64us will turn off CH7. CN Function High RTC LDO Low SW1 SW1 SW1 is an open drain controller to drive an external P-MOSFET and then functions as a load disconnect switch for CH1. This switch features soft start, Power On/ Off Sequence and under voltage protection functions. OK is an open drain control pin. Once CH1, CH3, CH4 and CH2's soft start finish, SW1 is on. The OK pin is slowly pulled low and controlled with soft start to suppress the inrush current. VOUT1 is used for SW1 soft start and under voltage protection. SW5 SW5 is an internal switch enabled by EN5 and functions as a load disconnection for CH5. This switch features soft start, Powe On Sequence, over voltage (for SW5I) and under voltage (for SW5O) protection functions. Charge Pumps The charge pump function is enabled while the PVDD6 voltage is lower than 3.6V. This channel provides pump voltage to enhance MOSFET gate driving capability. This function is not necessary while battery is Li-ion type. Reference Voltage The RT9919 provides a precise 1.25V reference voltage with souring capability of 100uA. Connect a 0.1uF ceramic capacitor from VREF pin to GND. Reference voltage is enabled by connecting EN6 to logic high. Furthermore, this reference voltage is internally pulled to GND at shutdown. www.richtek.com 18 RTC Reset The RT9919 provides an accurate voltage detector for RTC LDO voltage detection. It is used to detect whether RTC LDO output voltage is ready or not. Its power pin is RTC_PWR and output pin is RTC_R. The output pin is an open drain N-MOSFET and the sink capability is above 4mA. Once the RTC_PWR pin reach 1.6V, it will count about 55ms, then the RTC_R go high. System Reset The RT9919 provides an accurate voltage detector. It is enabled by EN1234 and used to detect whether VOUT1 (SW1)/VOUT2 and VOUT3 output voltage are ready or not. Its output pin (SYS_R) is an open drain N-MOSFET and the sink capability is above 4mA. Once Vout1 (SW1) voltage reaches 3V and FB3 voltage reaches 0.72V (90% of 0.8V), it will count about 10ms, then SYS_R go high for alkaline battery application. Once the FB2 and FB3 voltage reach 0.72V, it will count about 10ms, then the SYS_R go high for Li-Ion battery application. Mode Setting Please refer to “Electrical Characteristics” for level of logic high or low. Table 3. Mode Setting SEL CH2 High Boost Low Buck DS9919-01 April 2011 RT9919 Power on/off sequence The Power On Sequence is : While EN1234 goes high, CH1 will be turned on to wait for the completion of CH1's soft start. After that, CH3 will be turned on to wait for the completion of CH3's soft start. And then, CH4 will be turned on to wait for the completion of CH4's soft start. Then, SW1 and CH2 will be turned on at the same time. Finally, SW1's soft start will be completed. The Power-Off Sequence is : At first, while EN1234 goes low, SW1 and CH2 (note 1) will be shutdown. After that, CH4 will be turned off and internally pulled low to wait for the completion of CH4's shutdown. And then, CH3 will be turned off and internally pulled low to wait for CH3's shutdown completion. Then, CH1 will be turned off and internally pulled low (note 2) to wait for CH1's shutdown completion. Finally, the whole IC will be shutdown (if EN5, EN6 and EN7 already go low). Note 1 : If CH2 is configured as a Boost, then the CH2 will not be internally pulled low and the completion of shutdown will not be checked. Note 2 : CH1 is configured as a Boost, so the CH1 will not be internally pulled low and the completion of shutdown will not be checked. Table 4. Power On/Off Sequence Power Sequence On CH1 → CH3 → CH4 → (SW1 and CH2) Off (SW1 and CH2) → CH4 → CH3 → CH1 Thermal Considerations For continuous operation, do not exceed absolute maximum operation junction temperature. The maximum power dissipation depends on the thermal resistance of IC package, PCB layout, the rate of surroundings airflow and temperature difference between junction to ambient. The maximum power dissipation can be calculated by following formula : PD(MAX) = (TJ(MAX) − TA ) / θJA Where T J(MAX) is the maximum operation junction temperature, TA is the ambient temperature and the θJA is the junction to ambient thermal resistance. For recommended operating conditions specification of RT9919, The maximum junction temperature is 125°C. The junction to ambient thermal resistance θJA is layout dependent. For WQFN-40L 5x5 packages, the thermal resistance θJA is 36°C/W on the standard JEDEC 51-7 four layers thermal test board. The maximum power dissipation at TA = 25°C can be calculated by following formula : PD(MAX) = (125°C − 25°C) / (36°C/W) = 2.778W for WQFN-40L 5x5 packages The maximum power dissipation depends on operating ambient temperature for fixed T J(MAX) and thermal resistance θJA. For RT9919 packages, the Figure 1 of derating curves allows the designer to see the effect of rising ambient temperature on the maximum power allowed. Maximum Power Dissipation (W) Mode setting is decided by the “SEL” pin. The CH2 of RT9919 features flexible boost or buck topology setting for either 1 x Li-ion or 2 x AA application by one pin. Please note that the logic state can not be changed during operation. 3.0 2.8 2.6 2.4 2.2 2.0 1.8 1.6 1.4 1.2 1.0 0.8 0.6 0.4 0.2 0.0 Four Layers PCB WQFN-40L 5x5 0 25 50 75 100 125 Ambient Temperature (°C) Figure 1. Derating Curves for RT9919 Packages DS9919-01 April 2011 www.richtek.com 19 RT9919 For the best performance of the RT9919, the following PCB layout guidelines must be strictly followed. } Place the feedback components as close as possible to the FB pin and keep these components away from the noisy devices. } Place the input and output capacitors as close as possible to the input and output pins respectively for good filtering. } Place the compensative components as close as possible to the COMP pin and keep these components away from the noisy devices. } Keep the main power traces as wide and short as possible. } Connect the GND and Exposed Pad to a strong ground plane for maximum thermal dissipation and noise Layout Considerations protection. } The switching node area connected to LX and inductor should be minimized for lower EMI. Place the feedback and compensation components as close as possible to the FB and COMP pin and keep away from noisy devices. LX should be connected to inductor by wide and short trace, keep sensitive components away from this trace. VOUT1_CH1 GND GND VBAT VOUT2_CH2 C2 R1 GND C6 R4 C5 C3 C7 R3 R2 C21 R5 R6 L1 LX1 SYS_R COMP1 FB1 OK VOUT1 FB2 COMP2 EN1234 LX2 C22 C1 C18 C19 C13 R9 R10 40 39 38 37 36 35 34 33 32 31 2 29 3 28 4 27 5 6 25 7 24 8 23 41 9 21 11 12 13 14 15 16 17 18 19 20 VBAT C11 C16 R15 VBAT D1 C23 D5 L7 WLED+ VBAT C10 C26 L5 C24 D3 VBAT GND C14 R8 R7 C10 L3 GND VOUT3_CH3 C9 C8 C15 R11 GND GND PVDD2 VDDM CFB7 GND LX7 LX5 VOUT7 FB3 EN7 LX3 R16 R12 VOUT4_CH4 22 10 L4 C12 26 GND D2 C4 30 1 VBAT VOUT6_CH6 L6 PVDD1 LX6 D4 PVDD6 C25 VBAT CP CN C17 PNEG R13 FB6 R14 FB4 EN6 LX4 WLED- PVDD4 EN5 SW5O SW5I FB5 VREF SEL RTC_R RTC_PWR PVDD3 Input/Output capacitors must be placed as close as possible to the Input/Output pins. L2 GND GND VOUT5_CH5 Connect the Exposed Pad to a ground plane. Figure 2. PCB Layout Guideline for Li-ion Application www.richtek.com 20 DS9919-01 April 2011 RT9919 Table 5. Protection Items Protection Threshold (typical) Protection methods type Refer to Electrical spec Over Voltage Automatic reset at VDDM VDDM > 6V Protection V DDM < 5.4V NMOS off, PMOS off, Current Limit NMOS current > 3A Automatic reset at next CH1 clock cycle Boost NMOS off, PMOS off, PVDD1 OVP PVDD1 > 6V Automatic reset at PVDD1 < 5.4V NMOS off, PMOS off, Current Limit NMOS current > 3A Automatic reset at next CH2 clock cycle Boost NMOS off, PMOS off, PVDD2 OVP PVDD2 > 6V Automatic reset at PVDD2 < 5.4V NMOS off, PMOS off, CH2 Current Limit PMOS current > 1.5A Automatic reset at next Buck clock cycle NMOS off, PMOS off, CH3 Current Limit PMOS current > 1.5A Automatic reset at next Buck clock cycle NMOS off, PMOS off, CH4 Current Limit PMOS current > 1.5A Automatic reset at next Buck clock cycle NMOS off CH5 Current Limit NMOS current > 1.2A Automatic reset at next Asyn Boost clock cycle PMOS off CH6 Current Limit PMOS current > 1.5A Automatic reset at next Inverting clock cycle NMOS off Current Limit NMOS current > 0.8A Automatic reset at next CH7 clock cycle WLED OVP VOUT7 > 14V Shutdown CH7 IC Shutdown Delay time 100ms V DDM power reset 100ms V DDM power reset 100ms V DDM power reset 100ms V DDM power reset 100ms V DDM power reset 100ms V DDM power reset 100ms V DDM power reset 100ms V DDM power reset 100ms V DDM power reset 100ms V DDM power reset Not Applicable Automatic reset at next clock cycle Not Applicable Reset by toggling EN7 100ms V DDM power reset 100ms V DDM power reset 100ms V DDM power reset UVP VOUT1 < 1.75V after SW1 soft start end OVP SW5I > 18V UVP SW5O < 0.4V after SW5 soft start end Automatic reset at VOUT1 > 1.75V NMOS off Automatic reset at SW5I < 18V Automatic reset at SW5O > 0.4V Thermal Thermal shutdown Temperature > 160°C All channels stop switching No-delay CH2 Buck UVP CH3 Buck UVP CH4 Buck UVP SW1 SW5 DS9919-01 April 2011 NMOS off, PMOS off, FB2 < 0.4V after CH2 soft Automatic reset at FB2 > start 0.4V NMOS off, PMOS off, FB3 < 0.4V after CH3 soft Automatic reset at FB3 > start 0.4V NMOS off, PMOS off, FB4 < 0.4V after CH4 soft Automatic reset at FB4 > start 0.4V Reset method Temperature < 140°C 100ms V DDM power reset 100ms V DDM power reset 100ms V DDM power reset www.richtek.com 21 RT9919 Outline Dimension D SEE DETAIL A D2 L 1 E2 E e b 1 1 2 2 DETAIL A Pin #1 ID and Tie Bar Mark Options A A3 A1 Symbol Note : The configuration of the Pin #1 identifier is optional, but must be located within the zone indicated. Dimensions In Millimeters Dimensions In Inches Min Max Min Max A 0.700 0.800 0.028 0.031 A1 0.000 0.050 0.000 0.002 A3 0.175 0.250 0.007 0.010 b 0.150 0.250 0.006 0.010 D 4.950 5.050 0.195 0.199 D2 3.250 3.500 0.128 0.138 E 4.950 5.050 0.195 0.199 E2 3.250 3.500 0.128 0.138 e L 0.400 0.350 0.016 0.450 0.014 0.018 W-Type 40L QFN 5x5 Package Richtek Technology Corporation Richtek Technology Corporation Headquarter Taipei Office (Marketing) 5F, No. 20, Taiyuen Street, Chupei City 5F, No. 95, Minchiuan Road, Hsintien City Hsinchu, Taiwan, R.O.C. Taipei County, Taiwan, R.O.C. Tel: (8863)5526789 Fax: (8863)5526611 Tel: (8862)86672399 Fax: (8862)86672377 Email: [email protected] Information that is provided by Richtek Technology Corporation is believed to be accurate and reliable. Richtek reserves the right to make any change in circuit design, specification or other related things if necessary without notice at any time. No third party intellectual property infringement of the applications should be guaranteed by users when integrating Richtek products into any application. No legal responsibility for any said applications is assumed by Richtek. www.richtek.com 22 DS9919-01 April 2011