TECHNICAL DATA Constant Voltage and Constant Current Controller for Adaptors and Battery Chargers IK3051A Description IK3051A is a highly integrated solution for SMPS applications requiring constant voltage and constant current mode. IK3051A integrates one voltage reference, two operational amplifiers (with ORed outputs – common collectors), and a current sensing circuit. The voltage reference combined with one operational amplifier makes it an ideal voltage controller, and the other low voltage reference combined with the other operational amplifier makes it an ideal current limiter for output low side current sensing. The current threshold is fixed and precise. The only external components are: • A resistor bridge to be connected to the output of the power supply (adapter, battery charger) to set the voltage regulation by dividing the desired output voltage to match the internal voltage reference value. • A sense resistor having a value and allowable dissipation power which need to be chosen according to the internal voltage threshold. • Optional compensation components (R and C). IK3051A, is ideal for smallest package available, is ideal for space shrinked applications such as adapters and battery chargers. Features • CONSTANT VOLTAGE AND CONSTANT CURRENT CONTROL • LOW VOLTAGE OPERATION • PRECISION INTERNAL COMPONENT COUNT • CURRENT SINK OUTPUT STAGE • EASY COMPENSATION • LOW AC MAINS VOLTAGE REJECTION Pin Definitions and Functions SOT23-6 Pinout Name Pin# Type Vcc 6 Power Supply GND 2 Power Supply Vctrl 1 Analog Input Ictrl 4 Analog Input Out 3 Current Sink Output Vsense 5 Analog Input Function Positive Power Supply Line Ground Line. 0V Reference For All Voltages Input Pin of the Voltage Control Loop Input Pin of the Current Control Loop Output Pin. Sinking Current Only Input Pin of the Current Control Loop Rev. 00 IK3051A Absolute Maximum Ratings Symbol Vcc Vi Top Tj Parameter DC Supply Voltage Input Voltage Operating Free Air Temperature Range Maximum Junction Temperature Value 14 -0.3 to Vcc 0 to 85 150 Unit V V o C o C Operation Conditions Symbol Vcc Parameter DC Supply Conditions Value 2.5 to 12 Unit V Electrical Characteristics Tamb = 25°C and Vcc = +5V (unless otherwise specified) Symbol Parameter Total Current Consumption Total Supply Current – not taking the Icc output sinking current into account Voltage Control Loop Transconduction Gain (Vctrl). Sink Gmv 1) Current Only Vref Voltage Control Loop Reference Iibv Input Bias Current (Vctrl) 2) Current Control Loop Transconduction Gain (Ictrl). Sink Gmi 3) Current Only 4) Vsense Current Control Loop Reference Iibi Current out of pin Ictrl at -200mV Output Stage Low output voltage at 10 mA sinking Vol current Output Short Circuit Current. Output Ios to Vcc. Sink Current Only Test Condition Min Tamb 0 < Tamb < 85°C Tamb 0 < Tamb < 85°C Tamb 0 < Tamb < 85°C Tamb 0 < Tamb < 85°C Tamb 0 < Tamb < 85°C Iout = 2.5 mA Tamb 0 < Tamb < 85°C Tamb 0 < Tamb < 85°C Tamb 0 < Tamb < 85°C Tamb 0 < Tamb < 85°C Typ Max 1.1 1.2 2 1 3.5 2.5 1.204 1.186 1.21 Unit mA mA/mV 1.216 1.234 V 50 100 nA 1.5 7 mA/mV 196 192 200 204 208 mV 25 50 µA 200 mV 27 35 50 mA 1. If the voltage on Vctrl (the negative input of the amplifier) is higher than the positive amplifier input (Vref=1.210V), and it is increased by 1mV, the sinking current at the output OUT will be increased by 3.5mA. 2. The internal Voltage Reference is set at 1.210V (bandgap reference). The voltage control loop precision takes into account the cumulative effects of the internal voltage reference deviation as well as the input offset voltage of the transconductance operational amplifier. The internal Voltage Reference is fixed by bandgap, and trimmed to 0.5% accuracy at room temperature. 3. When the positive input at Ictrl is lower than -200mV, and the voltage is decreased by 1mV, the sinking current at the output OUT will be increased by 7mA. 4. The internal current sense threshold is set to -200mV. The current control loop precision takes into account the cumulative effects of the internal voltage reference deviation as well as the input offset voltage of the trans-conduction operational amplifier. Rev. 00 IK3051A Figure 1 : Typical Adapter or Battery Charger Application Using IK3051A In the above application schematic, the IK3051A is used on the secondary side of a flyback adapter (or battery charger) to provide an accurate control of voltage and current. The above feedback loop is made with an optocoupler. Rev. 00 IK3051A Figure 3: Vref vs Ambient Temperature Figure 4: Vsense pin input bias current vs Ambient Temperature Figure 5: Output short circuit current vs Ambient Temperature Figure 6: Vsense vs Ambient Temperature Figure 7: Ictrl pin input bias current vs Ambient Temperature Figure 8: Supply current vs Ambient Temperature Rev. 00 IK3051A PACKAGE DIMENSION SOT-23-6 Symbol A A1 A2 b c D E E1 e e1 L L1 θ Dimensions In Millimeters Min 1.050 0.000 1.050 0.300 0.100 2.820 1.500 2.650 Max 1.250 0.100 1.150 0.500 0.200 3.020 1.700 2.950 Dimensions In Inches Min 0.041 0.000 0.041 0.012 0.004 0.111 0.059 0.104 0.950TYP 1.800 0.037TYP 2.000 0.071 0.600REF 0.300 0° Max 0.049 0.004 0.045 0.020 0.008 0.119 0.067 0.116 0.079 0.024REF 0.600 8° 0.012 0° 0.024 8° Rev. 00