iP7700 用于交流转直流电源的定电压定电流控制芯片 1. 功能说明 2. 芯片特色 iP7700 是一个应用于开关电源中二次侧高度集成控 制芯片,应用于双重控制,定电压模式（CV）和定电 流模式(CC).此芯片整合电压参考电路以及两个 OP 放大器(OR-ed open-drain 输出)以及电流感测电 路。 芯片的外部电路需要一个电阻分压去侦测电压输 出，取样电阻侦测电流输出并调整功率消耗，以及 频率补偿组件回路。 z z z z z 二次测的电压/电流控制 2.5V-40V 操作范围 极低的quiescent consumption 较少的外部组件 SOT23-6L 封装 3. 应用领域 z z z 电池充电器 AC / DC 适配器 LED 照明 4. 引脚外观 SOT23-6L 1 www.saiertong.com 0755-82732291 Version 1.2 iP7700 5.外观打印方式 Product Name Marking iP7700 7700X X : Date Code 6. 订购信息编码 Assembly Material G: Halogen and Lead Free Device Note: inergy defines “Green” as lead-free ( RoHS compliant) and halogen free (Br or Cl does not exceed 900 ppm by weight in homogeneous material and total of Br and Cl does not exceed 1500 ppm by weight ; Follow IEC 61249-2-21 and IPC/JEDEC J-STD-020C ) 7. 引脚定义 Pin Name Description 1 Vctrl 电压回路OP放大器的非反向输入端。此引脚必需连接到输出电压的分压侦测 电阻中间点。 2 GND 接地引脚。此引脚连接时要尽量接近系统的GND以避免负载电流对芯片精度造 成干扰。 3 OUT 内部的2 个OP 放大器的Common open-drain 输出引脚。 4 Ictrl 电流回路OP放大器的非反向输入端。 5 Vsense 6 Vcc 电流回路OP放大器的反向输入端。 芯片电源引脚。外接一个 0.1uF 的bypass电容到GND，此电容要尽量接近IC 引脚以提供较稳定的电源。 2 www.saiertong.com 0755-82732291 Version 1.2 iP7700 8.电路方块图 9. 绝对操作范围 Symbol Parameter Value Unit VCC DC supply voltage ( Pin 6 ) - 0.3 to 40 V VOUT Open-drain voltage ( Pin 3 ) - 0.3 to 40 V IOUT Max sink current ( Pin 3 ) 100 mA Analog inputs ( Pin 1, 4, 5 ) - 0.3 to 3.3 V Parameter Value Unit 250 ºC / W V 10.熱阻及溫度資料 Symbol RthJA Thermal resistance, junction-to-ambient TOP Junction temperature operating range Tjmax Maximum junction temperature TSTG Storage temperature -40 to 100 150 ºC -55 to 150 3 www.saiertong.com 0755-82732291 Version 1.2 iP7700 11. 标准电气特性数值( TJ = 25 ºC and VCC = 5 V, unless otherwise specified ) Symbol Parameter Conditions Min. Typ. Max. Unit 2.5 - 40 V - 70 - uA 1.5 7 - S 196 200 204 192 - 208 20 - uA 1 2 - S 1.198 1.21 1.222 1.186 - 1.234 Device supply VCC Voltage operating range ICC Quiescent current ( Ictrl = Vsense = Vctr = 0,OUT = open ) Current control loop Gmi Transconductance ( sink current only ) (2) Vsense Current loop reference @ I(Iout) = 1 mA Ibias (1) Non-inverting input source current @ V(Ictrl) = -200 mV - mV Voltage control loop op amp Gmv Transconductance ( sink current only ) (3) Vref Voltage reference Ibias Inverting input bias current - 50 - nA Low output level @ 2 mA sink current - 75 - mV (1) V Output stage VOUTlow 1. 2. 3. Specification referred to - 40 ºC ＜ TA ＜ 100 ºC When the positive input at Ictrl is lower than - 200 mV, and the voltage is decreased by 1mV, the sinking current at the output Out will be increased by 7 mA. If the voltage on Vctrl ( the negative input of the amplifier ) is higher than the positive amplifier input ( Vref = 1.21 V ), and it is increased by 1mV, the sinking current at the output OUT will be increased by 2 mA. 4 www.saiertong.com 0755-82732291 Version 1.2 iP7700 12. 标准电气特性图形 5V 1.23 18V 40V 18V 40V 202 Vsense (mV) 1.22 Vref (V) 5V 204 1.21 1.20 1.19 -50 -25 0 25 50 200 198 196 -50 -25 75 100 125 150 5V 150 18V 0 25 50 75 100 125 150 Temperature (8C) Figure 2. Vsense vs. ambient temperature Temperature (8C) Figure 1. Vref vs. ambient temperature 40V 5V 30 18V 40V 27 Iibi (uA) Icc (uA) 100 50 24 21 18 0 -50 -25 0 25 50 15 -50 -25 75 100 125 150 Temperature (8C) Figure 3. Supply current vs. ambient temperature 5V 10 18V 40V 5V 10 50 75 100 125 150 18V 40V 8 Gmi (mA/mV) Gmv (mA/mV) 25 Temperature (8C) Figure 4. ICTRL pin input bias current vs. ambient temperature 8 6 4 2 0 -50 -25 0 6 4 2 0 25 50 0 -50 -25 75 100 125 150 Temperature (8C) Figure 5. Transconductance(sink current only) of voltage control loop Op-Amp vs. ambient temperature 0 25 50 75 100 125 150 Temperature (8C) Figure 6. Transconductance(sink current only) of current control loop Op-Amp vs. ambient temperature 5 www.saiertong.com 0755-82732291 Version 1.2 iP7700 12. 标准电气特性图形(续) 5V 18V 40V 100 50 0 -50 -25 0 25 50 5V 50 40V 60 50 50 40 30 10 10 50 50 75 100 125 150 5V 0 -50 -25 75 100 125 150 Temperature (8C) Figure 9. Output short circuit current of voltage control loop Op-Amp vs. ambient temperature 18V 40V 30 20 25 25 40 20 0 0 70 60 0 -50 -25 40V Temperature (8C) Figure 8. Low output level of current control loop Op-Amp vs. ambient temperature (2mA sink current) Iosc (mA) Iosv (mA) 18V 18V 100 0 -50 -25 75 100 125 150 Temperature (8C) Figure 7. Low output level of voltage control loop Op-Amp vs. ambient temperature (2mA sink current) 70 5V 150 Volc (mV) Volv (mV) 150 0 25 50 75 100 125 150 Temperature (8C) Figure 10. Output short circuit current of current control loop of Op-Amp vs. ambient temperature 2.5 Vol (V) 2.0 1.5 1.0 0.5 0.0 0 4 8 12 16 20 24 28 32 36 Isink (mA) Figure 11. Low output level vs. sink current 6 www.saiertong.com 0755-82732291 Version 1.2 iP7700 13. 应用电路 13.1 Typical application schematic R1 Rled 6 VCC Vctrl 1 5 VSENSE GND 2 4 Ictrl OUT 3 Rvc1 R2 Vout Cvc1 1KΩ Cic1 Ric1 Ric2 Rsense 13.2 Voltage and current control 13.2.1 Voltage control The voltage loop is controlled via a first transconductance operational amplifier, the voltage divider R1, R2, and the optocoupler which is directly connected to the output. VOUT can be assigned by choosing the values of R1 and R2 resistors using Equation 1: Equation 1 VOUT = Vref i (R + R ) 1 2 R2 where Vout is the desired output voltage, and Vref is the threshold voltage for the voltage control loop. As an example, with R1 = 150 kΩ and R2 = 10 kΩ, VOUT = 19.36 V. 7 www.saiertong.com 0755-82732291 Version 1.2 iP7700 13.2.2 Current control The current loop is controlled via the second transconductance operational amplifier, the sense resistor Rsense, and the optocoupler. The control equation verifies: Equation 2 a) Rsense i Ilim = Vsense b) Rsense = Vsense Ilim where Ilim is the desired limited current, and VSENSE is the threshold voltage for the current control loop. As an example, with Ilim = 1 A, Vsense = 200 mV, then Rsense = 200 mΩ. Note : The Rsense resistor should be chosen taking into account the maximum dissipation ( Plim ) through it during full load operation. Equation 3 Plim = Vsense i Ilim As an example, with Ilim = 1 A, and VSENSE = 200 mV, Plim = 200 mW. Therefore, for most adapter and battery charger applications, a quarter-watt, or half-watt resistor is sufficient. VSENSE threshold is made internally by a voltage divider tied to the Vref voltage reference. Its middle point is tied to the positive input of the current control operational amplifier, and its foot is to be connected to lower potential point of the sense resistor. The resistors of this voltage divider are matched to provide the best possible accuracy. The current sinking outputs of the two transconductance operational amplifiers are common ( to the output of the IC ). This makes an ORing function which ensures either the voltage control or the current control, driving the optocoupler’s photodiode to transmit the feedback to the primary side. The relation between the controlled current and the controlled output voltage can be described with a square characteristic as shown in the following V/I output-power diagram. ( with the power supply of the device independent of the output voltage ) 8 www.saiertong.com 0755-82732291 Version 1.2 iP7700 Output voltage versus Output current 13.3 Compensation The voltage control transconductance operational amplifier can be fully compensated. Both of its output and negative input are directly accessible for external compensation components. An example of a suitable compensation network is shown in typical application schematic. It consists of a capacitor CVC1 = 47 nF and a resistor RVC1 = 470 kΩ in series. The current control transconductance operational amplifier also can be fully compensated. Both of its output and negative input are directly accessible for external compensation components. An example of a suitable compensation network is shown in typical application schematic. It consists of a capacitor CiC1 = 100 nF and a resistor RIC1 = 10 kΩ in series. In order to increase the stability of the application, the circuit could to add a resistor in series with the optocoupler. An example of a suitable Rled value could be 10 kΩ in series with the optocoupler. 9 www.saiertong.com 0755-82732291 Version 1.2 iP7700 14. 封装信息 SOT23-6L Symbol A A1 A2 D E E1 c b e e1 L Dimensions In Millimeters MIN. ── ── MAX. 1.45 0.15 1.30 0.90 2.90 BSC 2.80 BSC 1.50 0.08 0.30 1.70 0.25 0.50 0.95 BSC 1.90 BSC 0.30 0.60 10 www.saiertong.com 0755-82732291 Version 1.2