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中小型面板之电源管理器件 及应用介绍

中小型面板之电源管理器件 及应用介绍. 郑刚 专案副理 http://www.richtek.com. LDO Linear Regulators for Mobile Phone Application LED Drivers for Display Backlighting PCB Layout Considerations for Mobile Phone Power Circuit. Outline. Back. LDO Linear Regulators for Mobile Phone Application. Back. Outline.

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中小型面板之电源管理器件 及应用介绍

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  1. 中小型面板之电源管理器件及应用介绍 郑刚 专案副理 http://www.richtek.com

  2. LDO Linear Regulators for Mobile Phone Application LED Drivers for Display Backlighting PCB Layout Considerations for Mobile Phone Power Circuit Outline Back

  3. LDO Linear Regulators for Mobile Phone Application Back

  4. Outline Fundamental Introduction of LDO LDO Topologies Important Characteristic of LDO Richtek LDOs for Cellular Phone Applications Back

  5. Fundamental Introduction of LDO What is LDO ? • Low Drop Out: A linear voltage regulator that will operate even when the input voltage barely exceeds the desired output voltage. Applications: • Cellular Phones • Notebook • PCMCIA Cards • Mother Board Power Supply • Cable Modems • Wireless LAN • …………………… Back

  6. I-V Characteristic of N-channel MOSFET NMOS Slop=1/Ri + Vo - Cutoff Region : VGS < Vt Linear Region : VDS < VGS-Vt Saturation Region: VDS > VGS-Vt Vds=VIN - Vo Boundary: Back

  7. LDO Topologies • The reference • The pass element 3. The sampling resistor 4. The error amplifier Four basic functional blocks: Back

  8. Load Regulation • Load regulation is a measure of the circuit’s ability to maintain the specified output voltage under varying load conditions. Load regulation is defined as: RT9182 Vo Back

  9. Line Regulation • Line regulation is a measure of the circuit’s ability to maintain the specified output voltage with varying input voltage. Line regulation is defined as: RT9182 Back

  10. Transient Response The transient response is an important specification, which is the maximum allowable output voltage variation for a load current step change. Back

  11. PSRR (Power Supply Rejection Ratio) This specification is the measure of how well the regulator rejects an AC signal riding on a nominal input DC voltage Back

  12. Improved PSRR One or more cascades of external RC filters LC filter An additional linear regulator Back

  13. Output Noise Voltage Output noise voltage is the RMS output noise voltage over a bandwidth (10Hz to 100KHz) under the conditions of a constant output current and a ripple-free input voltage. The noise generated only by the LDO itself. Back

  14. The LDO output noise can be reduced by effective LDO internal design and external bypass and compensation Back

  15. Thermal Resistance or Back

  16. Design Example A 2.5V system using RT9198 to supply Vo= 2.5V VI-max= 4.2V 1. 100mA duty cycle D1 = 0.378/4.61=8.2%; 60mA duty cycle D2=91.8% • PD(100mA) = (Vi-Vo)Io+(Vi x Iq) = (4.2V-2.5V)100mA + (4.2V x 130uA) = 170.55mW PD(60mA) = (4.2V-2.5V)60mA + (4.2 x 130uA)= 102.55mW 3. PD(total) = PD(100mA) x D1 + PD(60mA) x D2 = 170.55mW x 8.2% + 102.55mW x 91.8% =108.13 mW The maximum power dissipation for RT9198 operating at an ambient temperature of 70℃: SOT-25: 220mW, SC-70: 165mW Back Selecting SC-70 package

  17. CMOS Camera Module Power Array Size 640X480 ( VGA ) Digital 2.5VDC ± 10% Analog 2.5VDC ± 4% DOVDD is 2.8~3.0V sensor digital IO power VDD CIF Dropout is not critical. ( Li-ion battery range from 3.2V to 4.2V) Require low-noise and high PSRR LDOs for AVDD. This LDO is not on all the time, so the quiescent current is not care. Small package. Back

  18. RT9167/A Low-Noise, 300mA/500mA LDO Regulator • Feature • Shutdown function • Low-Dropout: 350mV at 300mA • Low Noise Output • Short circuit and thermal protection function • SOT-25 package RT9178 Ultra Low Noise, High PSRR LDO Regulator • Feature • 50uV Ultra-Low Output Noise • Quick Start-up ( Typical 100us) • Low-Dropout: 200mV at 200mA • High PSRR • SOT-25 package Back

  19. RT9182 Dual, Low-Noise, 200mA LDO Regulator • Feature • Dual shutdown pin control each output • Low-Dropout: 120mV at 100mA • 124uVrms Low Noise Output • Short circuit and thermal protection function • SOT-26 package RT9198 300mA, High PSRR LDO Regulator • Feature • <0.01uA quiescent current when shutdown • Low-Dropout: 220mV at 300mA • High PSRR and ultra-low-noise for phone application • SOT25/SC-70 package Back

  20. LED Drivers for Display Backlighting Back

  21. Outline Features of White LED Driver Solutions for WLED Efficiency Analysis RichTek Solutions for WLED Driver Backlight Driver Solutions for Dual Panels Back

  22. Brightness is proportional to CURRENT Most popular LED currents (ILED) for backlight:10~15mA (for camera flash: 50~120mA) LED forward voltage (VLED): Can range from 3V to 4Vtypically. Most common: 3.3V~3.6V Forward voltage is a measure of efficiency of the LED… does not affect brightness much The LED with the higher VLED for a given current burns more power (VxI) White LED Background Info Back

  23. Parallel Connection No inductor requirement Low EMI Series Connection Lighting uniformity Higher efficiency Higher current capability Easy layout Panel Panel VDD EXT VDD WLED Driver LX WLED Driver FB CE CE GND GND Charge Pump Topology Boost Topology White LED Connection Back

  24. WLED Driver Solution for Backlight Panel VDD Panel CP VDD LX CS Boost CE FB CE GND Charge Pump with RT9362 Current source Topology RT9360 Boost Topology RT9271 Panel Panel VDD VDD CP CS CE CE Low VF LED Same VF LED Charge Pump Topology RT9361 Current source Topology RT9300

  25. WLED Driver Solution - Boost Converter CCM S on , 0＜t＜ton S off , ton＜t＜toff From volt-second balance principle Back

  26. WLED Driver Solution - Boost Converter Back

  27. WLED Driver Solution - Boost Converter DCM S on , 0＜t＜t1 S off , t1＜t＜t2 S off , D off, t2＜t＜T Back

  28. WLED Driver Solution - Boost Converter Back

  29. WLED Driver Solution - Charge Pump On State During the on state, Q1 and Q4 are closed, which charge C1 to VIN Off State During the off state, Q3 and Q2 are closed. The output voltage is VIN plus VC1, that is 2VIN Back

  30. LED Driver Efficiency vs. Converter Efficiency LED Driver Efficiency = “Power delivered to the LEDs” ÷ “Power drawn by the Input” LED Driver Efficiency = PLED ÷ PIN = (NxVLEDxILED) ÷ (VINxIIN) Converter Efficiency = “Power delivered to the Output pin” ÷ “Power drawn by the Input” Converter Efficiency= POUT ÷ PIN = (VOUTxIOUT) ÷ (VINxIIN) • Converter Efficiency does not account for Power losses of external ballast resistors • LED Driver Efficiency & Converter Efficiency confusion can always be avoided by comparing “INPUT POWER” Back

  31. Efficiency - Example • Parallel Connection – Charge Pump • LED Power (PLED)= VF * IOUT * 3 = 3.5 * 20mA * 3 = 210mW • Input Power (PIN)= VOUT * IOUT / Converter Efficiency = 5V * 20mA * 3 / 0.85 = 352.9mW • LED Driver Efficiency = PLED / PIN = 59.5% • Series Connection – Boost • LED Power (PLED)= VF * 3 * IOUT = 3.5 * 3 * 20mA = 210mW • Input Power (PIN)= VOUT * IOUT / Converter Efficiency = (3.5 * 3 + 0.25)V * 20mA / 0.85 = 252.9mW • LED Driver Efficiency = PLED / PIN = 83% • Assumption • Test Condition is in 3 WLEDs – Mobile phone application • Forward voltage of WLED is 3.5V and output current is 20mA • The converter efficiency of boost and charge pump is the same as 85% • The output of charge pump is about 5V • The feedback of boost is 0.25V Back

  32. WLED Driver Solution - Charge Pump The amount of charge flowing into C1 during on state is equal to that flowing out of C1 at off state The efficiency of charge pump is given below: Back

  33. LCM Power Solution White LED Driver • Single Panel - RT9271 (Boost DC/DC Converter) - RT9360 (Charge Pump + Current Source) - RT9362(Charge Pump + Current Source) - RT9361 (Charge Pump) - RT9300 (Current Source) • Dual Panel - RT9272 (TFT/CSTN + TFT/CSTN) - RT9273 (TFT/CSTN + OLED) Back

  34. Power Solution RT9271 White LED Boost converter with OVP • Feature • High Efficiency: 85% typical • 20V Internal Switch • Fast 1.1MHz Switching Frequency • Requires Only 1uF Input/Output Capacitor • Low FB Voltage - 0.25V • Optional 15V Over Voltage Protection • Support camera flash application • Low Profile SOT-25/26 Package • Typical Application Up to 80mA peak Back

  35. VDD Panel OVP LX VCC FB GND CE CE Power Solution RT9271 White LED Boost converter with OVP • Function Block Diagram Back

  36. Power Solution RT9271 White LED Boost converter with OVP • Dimming Control Using a PWM Control Using a Logic Signal RT9271 FB RT9271 CEFB Using a DC Voltage Using a Filtered PWM Control RT9271 FB RT9271 FB 200~1KHz Back

  37. Power Solution Inductor Selection • Inductance value • ESR: copper loss • Magnetic loss • Saturation • Current Rating • Operation frequency • Leakage & Noise • Height Back

  38. Power Solution RT9360 High Efficiency Charge Pump WLED Driver • Feature • Peak efficiency over 92% • Current Regulation for up to 4WLEDs • Digital 3 bit output control logic • Soft-start, short circuit protection function • Three charge pump modes of operation • Support camera flash application • QFN-4x4 package • Typical Application Up to 200mA peak Back

  39. Power Solution RT9362 High Efficiency Charge Pump WLED Driver • Feature • Everything is the same as RT9360 • But has smaller size and different pin definition • QFN-3x3 package • Typical Application Up to 200mA peak Back

  40. C1P C1N C2P C2N VDD VIN VOUT Panel GND ISET EN EN LED1 LED2 LED3 LED4 CTRL0 CTRL1 CTRL2 Control Inputs Power Solution RT9360 High Efficiency Charge Pump WLED Driver • Function Block Diagram Back

  41. Power Solution RT9360 High Efficiency Charge Pump WLED Driver • Efficiency RT9360 (1x, 1.5x 2x CP+CS) Efficiency: 85%~95% Back

  42. Power Solution RT9360 High Efficiency Charge Pump WLED Driver • Dimming Control Using a PWM Control Using a DC Voltage Back

  43. Power Solution RT9360 High Efficiency Charge Pump WLED Driver • Dimming Control Using a Logic Signal Back

  44. Ccp 0.22uF/ C- C+ VOUT= 5V VIN= 2.8~4.5V VDD VOUT C C OUT IN CE GND 2.2uF 2.2uF White LED for Backlight RT9361 120mA, Regulated Charge Pump • Feature • Useful for Same VF WLED Application ( VF difference < 0.1V) • Step Up type Voltage Converter • 1Mhz Frequency Operation Allows Small Capacitor • Short Circuit and Over Temperature Protection • Tiny Small Package SOT-26 Back

  45. VMBAT LED2 LED3 LED4 LED1 PWM CE GND White LED for Backlight RT9300 80mA, Current Regulator • Feature • Useful for Low VF WLED Application • No External Components • Very Low Internal Dropout Voltage(60mV) • Initial Current Sink 20mA/15mA • Tiny Small Package SOT-26 • PWM Dimming Control No External Components! Back

  46. Dual Panel Solution CSTN/TFT + CSTN/TFT Dual Channel powers Main and Sub-Displays Back CSTN/TFT + OLED

  47. Power Solution RT9272 Constant Current WLED Driver for Dual Panel Mobile Phone • Feature • Low Vin operating range: 2.4~6V • Maximum output voltage up to 16V • 1.4MHz Switching Frequency • Share one set of inductor and Schottky diode for 2 channel • Complete protection: OVP, OCP, OTP and SS • DFN3x3-10 Package • Typical Application Back

  48. Power Solution RT9273 OLED + WLED Driver for Dual Panel Mobile Phone • Feature • Low Vin operating range: 2.7~4.5V • Maximum output voltage up to 16V • 1.1MHz Switching Frequency • Share one set of inductor and Schottky diode for 2 channel • Complete protection: OVP, OCP, OTP and SS • DFN3x3-10 Package • Typical Application Back

  49. PCB Layout Considerations for Mobile Phone Power Circuit Back

  50. Outlines Introduction Routing the DC/DC Converter Power Stage The Right Connection of IC Controller Other Considerations Back

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