TSM1014

TSM1014 Low Consumption Voltage and Current Controller for Battery Chargers and Adaptors s s s s s s s s Constant voltage and constant current control Low consumption Low voltage operation Low external component count Current sink output stage Easy compensation High ac mains voltage rejection 2kV ESD protection (HBM) D SO-8 (Plastic Package) Voltage Reference: s s Fixed output voltage reference 1.25V 0.5% and 1% Voltage precision S MiniSO-8 (Plastic Micropackage) DESCRIPTION TSM1014 is a highly integrated solution for SMPS applications requiring CV (constant voltage) and CC (constant current) mode. TSM1014 integrates one voltage reference and two operational amplifiers. The voltage reference combined with one operational amplifier makes it an ideal voltage controller. The other operational amplifier, combined with few external resistors and the voltage reference, can be used as a current limiter. PIN CONNECTIONS (top view) 1 Vref 2 Cc3 Cc+ 4 Cv- Vcc 8 Cc Out 7 Gnd 6 Cv Out 5 APPLICATIONS s s Adapters Battery chargers ORDER CODES Part Number TSM1014ID TSM1014IDT TSM1014AID TSM1014AIDT TSM1014IST TSM1014AIST Temperature Range Package Packaging Tube Tape & Reel Tube Tape & Reel Tape & Reel Tape & Reel VRef (%) 1 1 0.5 0.5 1 0.5 Marking M1014 M1014 M1014A M1014A M808 M809 SO-8 -40 to 105°C mini SO-8 July 2004 Revision 1 1/10 TSM1014 1 Pin Descriptions Name VRef CCCC+ CVCVOUT Gnd CCOUT Vcc Pin # 1 2 3 4 5 6 7 8 Type Analog Output Analog Input Analog Input Analog Input Analog Output Power Supply Analog Output Power Supply Function Voltage Reference Input pin of the operational amplifier Input pin of the operational amplifier Input pin of the operational amplifier Output of the operational amplifier Ground Line. 0V Reference For All Voltages Output of the operational amplifier Power supply line. Pin Descriptions The table below gives the pin descriptions for both SO8 & MiniSO8 packages. 2 Absolute Maximum Ratings DC Supply Voltage DC Supply Voltage (50mA =< Icc) Input Voltage Power dissipation Operational temperature Storage temperature Junction temperature Voltage reference output current Electrostatic Discharge Thermal Resistance Junction to Ambient Mini SO8 package Thermal Resistance Junction to Ambient SO8 package Value -0.3V to Vz -0.3 to Vcc 0 to 105 -55 to 150 150 2.5 2 180 175 Unit V V W °C °C °C mA kV °C/W °C/W Symbol Vcc Vi PT Toper Tstg Tj Iref ESD Rthja Rthja 3 Operating Conditions Parameter DC Supply Conditions Operational temperature Value 4.5 to Vz -40 to 105 Unit V °C Symbol Vcc Toper 2/10 Electrical Characteristics 4 Electrical Characteristics Parameter Test Condition Min Typ Max TSM1014 Tamb = 25°C and Vcc = +18V (unless otherwise specified) Symbol Unit Total Current Consumption Icc Vz Total Supply Current, excluding current in Voltage Reference1. Vcc clamp voltage Vcc = 18V, no load Tmin. < Tamb < Tmax. Icc = 50mA 100 28 180 µA V Operator 1: Op-amp with non-inverting input connected to the internal VRef Input Offset Voltage + Voltage reference Tamb = 25°C TSM1014 Tmin. ≤ Tamb ≤ Tmax. Tamb = 25°C TSM1014A Tmin. ≤ Tamb ≤ Tmax. 1.251 1.25 VRef+Vio 1.266 1.279 1.258 1.267 V DVio Input Offset Voltage Drift 7 µV/°C Operator 2 Input Offset Voltage TSM1014 Vio TSM1014A Input Offset Voltage Drift Input Bias Current Supply Voltage Rejection Ration Input Common Mode Voltage Range Common Mode Rejection Ratio Tamb = 25°C Tmin. ≤ Tamb ≤ Tmax. VCC = 4.5V to 28V Tamb = 25°C Tmin. ≤ Tamb ≤ Tmax. Tamb = 25°C Tmin. ≤ Tamb ≤ Tmax. Tmin. ≤ Tamb ≤ Tmax. Tamb = 25°C Tmin. ≤ Tamb ≤ Tmax. 6 5 65 0 70 60 85 Tamb = 25°C Tmin. ≤ Tamb ≤ Tmax. Tamb = 25°C Tmin. ≤ Tamb ≤ Tmax. 4 5 2 3 150 200 Vcc-1.5 1 0.5 7 20 50 100 mV DVio Iib SVR Vicm CMR µV/°C nA dB V dB Output stage Gm Vol Ios Transconduction Gain. Sink Current Only2 Low output voltage at 5 mA sinking current Output Short Circuit Current. Output to (Vcc-0.6V). Sink Current Only 0.5 1 1 250 10 400 mA/mV mV mA Voltage reference Reference Input Voltage TSM1014 1% precision VRef TSM1014A 0.5% precision Tamb = 25°C Tmin. ≤ Tamb ≤ Tmax. Tamb = 25°C Tmin. ≤ Tamb ≤ Tmax. Tmin. ≤ Tamb ≤ Tmax. Iload = 1mA Vcc = 18V, 0 < Iload < 2.5mA 1.238 1.225 1.244 1.237 1.25 1.25 20 1.262 1.273 1.256 1.261 30 20 10 V Reference Input Voltage Deviation Over Temperature Range Reference input voltage deviation over RegLine Vcc range. Reference input voltage deviation over RegLoad output current. ∆VRef mV mV mV 1) Test conditions: pin 2 and 6 connected to GND, pin 4 and 5 connected to 1.25V, pin 3 connected to 200mV. 2) The current depends on the voltage difference between the negative and the positive inputs of the amplifier. If the voltage on the minus input is 1mV higher than the positive amplifier, the sinking current at the output OUT will be increased by Gm*1mA. 3/10 TSM1014 Figure 1: Internal schematic Electrical Characteristics 1 Vref Vref 28V Vcc 8 2 CcCC Ccout 7 3 Cc+ Gnd 6 4 Cv- CV Cvout 5 Figure 2: Typical adapter or battery charger application using TSM1014 Vcc Rlimit D To primary OUT+ 1 DS Vcc Vref 28V R3 100 CV CV Out 8 R2 IL 5 4 + 7 Rvc1 22K Cvc1 2.2nF R1 Load Cic1 2.2nF OUT- R4 100K CvCc+ 3 TSM1014 CC CC Out CS + + Cc- Gnd 2 6 Ric1 22K R5 Vsense 10K Rsense IL Ric2 1K In the application schematic shown in Figure 2, the TSM1014 is used on the secondary side of a flyback adapter (or battery charger) to provide an accurate voltage and current control. The above feedback loop is made with optocoupler. 4/10 Principles of Operation and Application Tips 5 Principles of Operation and Application Tips TSM1014 5.1 Voltage control The voltage loop is controlled via a first trans-conductance operational amplifier, the resistor bridge R1, R2, and the optocoupler which is directly connected to the output. The relation between the values of R1 and R 2 should be chosen as written in Equation 1. R1 = R2 x VRef / (Vout - VRef) where Vout is the desired output voltage. To avoid the discharge of the load, the resistor bridge R1, R2 should be highly resistive. For this type of application, a total value of 100KΩ (or more) would be appropriate for the resistors R1 and R2. As an example, with R2 = 100KΩ, Vout = 4.10V, VRef) = 1.210V, then R1 = 41.9KΩ. Note that if the low drop diode is inserted between the load and the voltage regulation resistor bridge to avoid current flowing from the load through the resistor bridge, this drop should be taken into account in the above calculations by replacing Vout by (Vout + Vdrop). Equation 1 5.2 Current control The current loop is controlled via the second trans-conductance operational amplifier, the sense resistor Rsense, and the optocoupler. Vsense threshold is achieved externally by a resistor bridge 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 as shown on the following figure. The resistors of this bridge are matched to provide the best precision possible. The control equation verifies: R sense × I lim = V sense R 5 ⋅ V ref V sense = ---------------------( R 4 + R5 ) R 5 ⋅ V ref ⋅ R sense I lim = --------------------------------------( R4 + R 5 ) Equation 2 Equation 3 where Ilim is the desired limited current, and Vsense is the threshold voltage for the current control loop. Note that the Rsense resistor should be chosen taking into account the maximum dissipation (Plim) through it during full load operation. P lim = I lim × V sense Equation 4 5/10 TSM1014 Principles of Operation and Application Tips Therefore, for most adapter and battery charger applications, a quarter-watt, or half-watt resistor to make the current sensing function is sufficient. The current sinking outputs of the two trans-conductance operational amplifiers are common (to the output of the IC). This makes an ORing function which ensures that whenever the current or the voltage reaches too high values, the optocoupler is activated. 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 graph. Figure 3: Output Voltage versus Output Current Vout Voltage regulation Current regulation 0 TSM1014 Vcc : independent power supply Secondary current regulation Iout TSM1014 Vcc : On power output Primary current regulation 5.3 Compensation The voltage-control trans-conductance operational amplifier can be fully compensated. Both its output and negative input are directly accessible for external compensation components. An example of a suitable voltage-control compensation network is shown in Figure 2 on page 4. It consists of a capacitor Cvc1=2.2nF and a resistor Rcv1=22KΩ in series. The current-control trans-conductance 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 current-control compensation network is also shown in Figure 2 on page 4. It consists of a capacitor Cic1=2.2nF and a resistor Ric1=22KΩ in series. 5.4 Start-up and short circuit conditions Under start-up or short-circuit conditions the TSM1014 is not provided with a high enough supply voltage. This is due to the fact that the chip has its power supply line in common with the power supply line of the system. Therefore, the current limitation can only be ensured by the primary PWM module, which should be chosen accordingly. If the primary current limitation is considered not to be precise enough for the application, then a sufficient supply for the TSM1014 has to be ensured under all conditions. For this, it would be necessary to add some circuitry to supply the chip with a separate power line. This can be achieved in a number of ways, including putting an additional winding on the transformer. 6/10 Principles of Operation and Application Tips 5.5 Voltage clamp TSM1014 The following schematic shows how to realize a low-cost power supply for the TSM1014 (with no additional windings).Please pay attention to the fact that in the particular case presented here, this lowcost power supply can reach voltages as high as twice the voltage of the regulated line. Since the Absolute Maximum Rating of the TSM1014 supply voltage is 28V. In the aim to protect he TSM1014 against such how voltage values a internal zener clamp is integrated. R limit = ( V cc – V z ) ⋅ I vz Figure 4: Clamp voltage Vcc Rlimit Ivz TSM1014 Vcc Vz 28V Figure 5: Voltage controller and over current detection schematic 1 Vcc Vref 28V To primary R3 1k Rvc1 22K CvCc+ CC CC Out Cvc1 2.2nF 8 CV OCP D OUT+ R2 R6 1K IL CV R4 100K CV Out 5 4 7 + 3 R1 + Cc- Gnd 2 6 Ric1 22K Cic1 2.2nF R5 Vsense 10K Rsense IL Ric2 1K OUT- Load 7/10 TSM1014 6 Package Mechanical Data Package Mechanical Data SO-8 MECHANICAL DATA DIM. A A1 A2 B C D E e H h L k ddd 0.1 5.80 0.25 0.40 mm. MIN. 1.35 0.10 1.10 0.33 0.19 4.80 3.80 1.27 6.20 0.50 1.27 0.228 0.010 0.016 TYP MAX. 1.75 0.25 1.65 0.51 0.25 5.00 4.00 MIN. 0.053 0.04 0.043 0.013 0.007 0.189 0.150 0.050 0.244 0.020 0.050 inch TYP. MAX. 0.069 0.010 0.065 0.020 0.010 0.197 0.157 8˚ (max.) 0.04 0016023/C 8/10 Package Mechanical Data TSM1014 9/10 TSM1014 7 Revision History Date 01 July 2004 Revision 1 First Release Description of Changes Revision History Information furnished is believed to be accurate and reliable. However, STMicroelectronics assumes no responsibility for the consequences of use of such information nor for any infringement of patents or other rights of third parties which may result from its use. No license is granted by implication or otherwise under any patent or patent rights of STMicroelectronics. Specifications mentioned in this publication are subject to change without notice. This publication supersedes and replaces all information previously supplied. STMicroelectronics products are not authorized for use as critical components in life support devices or systems without express written approval of STMicroelectronics. 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