ICs for CD/CD-ROM Player AN8083S Low Voltage Operation IC for DC-DC Converter ■ Overview 0.4 0.4±0.25 16 2 15 3 14 4 13 5 12 6 11 7 10 8 9 0.15 0.65 0.1±0.1 1.5±0.2 1.27 ■ Features • Operatable with low voltage input (PVCC>1.1V) • Decreased voltage detection circuit built-in • Short-circuit protection feature built-in • Provided with reset output • Synchronizable with outside clock • Low consumption current in stand-by mode • Output voltage in secondary side; 4.8V+0.3V (Variable 1 10.1±0.3 Unit : mm The AN8083S is an IC for controlling a DC-DC converter suitable for the switching power supply of various portable equipments. It can operate with input voltage 1.1V or more. 0.3 4.2±0.3 6.5±0.3 by using external resistance) 16-lead SOP package (SOP016-P-0225A) ■ Block Diagram RESET VCC EMP 15 16 13 VSEN START CT VREF 14 10 7 12 2.15V VREF 0.85V 0.25V + – 4.2V + – Triangular Wave Starter Starter SW 4.8V 9 CLK 8 PVCC 3.0 → 2.5V 1.25V 2.0V + – –25µA 1.25V 0.7V Early Value Set. + – – + Power OFF – + + 30kΩ 11 POWER Switching Circuit 0.9V 0.725V 6 63kΩ 1 2 3 4 5 IN FB SPRO DED OUT GND ICs for CD/CD-ROM Player AN8083S ■ Absolute Maximum Ratings (Ta=25˚C) Parameter Symbol Rating VCC 14.4 PVCC 14.4 Supply Voltage Unit V Power Dissipation PD 380 Operating Ambient Temperature Topr –20 ~ +75 ˚C Storage Temperature Tstg –55 ~ +125 ˚C mW ■ Recommended Operating Range (Ta=25˚C) Paramenter Operating Supply Voltage Range Symbol Range VCC 1.8V ~ 12V PVCC 1.1V ~ 12V ■ Electrical Characteristics (Ta=25˚C) Parameter Symbol Power VCC Stand-by Mode Supply Current IPVCC VCC=0V, PVCC=3V Power VCC Operating Mode Supply Current IPVCC VCC=3.1V, PVCC=3V Output Voltage Condition min. typ. max. 1.2 VO Unit 2 µA 3 mA 4.8 V Reset Output Threshold Voltage VTH (RESET) PVCC=3V 4 4.2 4.4 V Decreased Voltage Detection Threshold Voltage VTH (VSEN) PVCC=3V 2.05 2.15 2.25 V Short-Circuit Protection Operating Voltage VO (SPRO) VIN=0V, VPOWER=2V 1.35 2.1 V Short-Circuit Protection Operating Voltage VO (SPRO) VIN=1V, VPOWER=0V 1.7 3.2 V Oscillation Frequency in Normal Operation fOSC1 60 70 80 kHz Oscillation Frequency at Start fOSC2 RREF=33kΩ, CT=330pF RREF=33kΩ, CT=330pF VCC=1.9V, PVCC=3V 80 100 120 kHz 1.2 1.6 V 0.4 V Output Voltage (Normal) VOH (OUT) IO= –20mA, VCT=0V Output Voltage (Normal) VOL (OUT) IO=20mA, VCT=1V Note) Unless otherwise specified, VCC=4.8V, PVCC=3V ■ Application Circuit 4.8V±0.3V + RESET VCC EMP 15 16 CT START VSENSE 13 14 10 2.15V 7 VREF 330pF VREF 33kΩ 12 0.85V 0.25V + 4.2V + – – Triangular Wave Starter 1.25V Starter SW 4.8V 3.0V→ 2.5V PVCC 8 Initial set 1.25V 0.7V 2.0V POWER – + + – Power OFF –25µA – + + + – CLK 9 30kΩ 11 SW circuit 0.725V 0.9V GND 1 2 IN 3 FB + 33kΩ 6 63kΩ 4 SPRO 47µF 100Ω 5 DED 0.01µF 0.01µF OUT 0.01µF * Connect Pin11 to the secondary side and Pin10 to GND at oscillation start. (Pin10 is always open.) ICs for CD/CD-ROM Player AN8083S ■ Pin Description Pin Description Pin No. Symbol 1 IN • Input pin for error amplifier • Threshold voltage ; 0.7V 2 FB • Output pin for error amplifier SPRO • Short-circuit protection input pin. If output of error amplifier does not become “L” when t=CVth/ISPRO output of IC is not switched. ISPRO=25µA Vth=0.9V 4 DED • Dead time control input. Maximum duty ratio set to 85%. Maximum duty ratio can be changed by installing external resistance between Pins 12 and 4. 5 OUT • Switching output pin Output current ; IO=20mA (max.) 6 GND • GND pin 3 • Triangular oscillating capacitor pin 7 T1 = CV CV T2 = I (Discharged) I (Charged) f= 1 T1+T2 CT V I Discharged=52µA I Charged=30µA V=0.58V In normal mode T1 T2 PVCC • DC voltage input pin Operates with 1.2V or more. 9 CLK • Clock input · It is used to synchronize triangular oscillation with clock input and operates at rise edge of clock. · The threshold level is TTL level. · It is open when not used. 10 START 11 POWER 8 • Start pin · Starts switching of starter · Threshold voltage, PVCC – 0.9V • Power ON/OFF pin Output ON/OFF switching pin (Output is off at “L.”) 12 VREF • Reference voltage pin · 1.25V output · Charged and discharged current of triangular oscillation is determined by external R. VREF – 0.7 I (Charged) = RREF+1kΩ I (Discharged) =1.40 × I (Charged) 13 EMP • Decreased voltage detection output pin “H” when detected by open collector output form 14 VSEN • Decreased voltage detection input pin · Threshold voltage ; 2.15V 15 Reset • Reset output pin · “H” when VCC becomes 4.2V or more · Open collector output form 16 VCC • DC voltage input pin Operates with 1.8V or more. ICs for CD/CD-ROM Player AN8083S ■ System Block Diagram 16 + VCC OUT 8 5 P–VCC AN8083S 1.5V Power SW 11 Power OFF at “L” Start 1.5V 9 10 CLK RESET 15 CPU SW EMP 13 Oscillation starts at “L.” “L” when the battery voltage is 2.15V or less. “H” when the secondary voltage is 4.2V or more. Oscillation synchronization signal 1) When Pin10 becomes “L” by operation of CPU or push switch, oscillation starts and boosted voltage is outputted to the secondary side. 2) When the secondary side voltage exceeds 3.6V, starter circuit is stopped and PWM operation is started by using the voltage in the secondary side as power supply. 3) When the secondary side voltage becomes 4.2V, Pin15 becomes “H” and CPU operation is started. 4) When “L” pulse is sent from CPU to Pin11, oscillation is stopped and it enters the stand-by mode. In this status consumption current is 2µA max. 5) For re-start, when Pin10 becomes “L” by operation of CPU or push switch, oscillation starts. ■ Supplementary Explanation • Operational Description When power VCC pin (Pin8) is connected to the supply output and start pin (Pin10) is set to “Low,” the triangular oscillation is outputted to CT pin (Pin7) and the rectangular wave to OUT pin (Pin5). In this condition, called start condition, PWM control is not obtained and only oscillation is repeated. By this oscillation at start, supply output is increased. This supply output voltage is inputted to VCC pin (Pin16) of the AN8083S. When the voltage of VCC pin becomes 3V or more, start oscillation is stopped and oscillation in normal operation is outputted. PWM control is started only after entering normal mode. The voltage switching between start and normal operation has 0.5V hysteresis. When power pin (Pin11) is set to “High” in normal operation, normal mode oscillation is started. In this status, output of the supply is 4.8V fixed. • Other features 1. Short-circuit protection feature For normal mode oscillation, when output/FB pin (Pin2) of error amplifier is in “High” condition, oscillation is stopped, since the power supply system is judged to be in an abnormal condition. With the time constant of discharged current ISPRO of SPRO pin (Pin3) and capacitor CSPRO, pin voltage is increased, and oscillation is stopped when it becomes 1.25V or more. During this time, when the error amplifier becomes “Low,” charged current no longer exits and SPRO is maintained to 0.9V. 2. Decreased voltage detection circuit When VSEN pin (Pin14) gets 2.15V or less, EMS pin (Pin13) gets “High.” 3. Reset output When VCC pin voltage is 4.2V or more, RST pin (Pin15) gets “High.” ICs for CD/CD-ROM Player AN8083S • Miscellaneous 1. Method for making output voltage variable VCC = 0.7V × (R1 + R2)/R2 R1 = RX // R3 R2 = RY // R4 ex) Where VCC = 5V, RX = 51kΩ RY = 7.5kΩ VCC (16) RX R3 =20.5kΩ IN (1) R4 =3.5kΩ RY 2. Method for making decreased voltage detection variable VSEN = R1 + R2 R2 × 1.25 R3 ex) VSEN = 3V VSEN = VSEN (14) R1 =7kΩ R1 + R2 + R3 R2 × 1.25 R2 =10kΩ R3 = 7kΩ However, take care that an external resistance causes different temperature characteristics. 3. Reset output When the output voltage is made variable, detection voltage changes. 16.86kΩ 15 16 51kΩ VCC = 4.8V→ 4.2V (No changes) VCC = 5V→ 4.27V 1.25V 3.64kΩ 1 7.5kΩ 3.5kΩ • Chopper type application 16 AN8083S 51kΩ 1 8 4.8V±0.3V 5 2 0.01µF 33kΩ 0.01µF 7.5kΩ 2SD1328 100Ω 0.01µF 2SD1328 100Ω