TSM1012 LOW CONSUMPTION VOLTAGE AND CURRENT CONTROLLER FOR BATTERY CHARGERS AND ADAPTORS ■ 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 VOLTAGE REFERENCE ■ FIXED OUTPUT VOLTAGE REFERENCE 1.25V ■ 0.5% AND 1% VOLTAGE PRECISION D SO-8 (Plastic Package) S MiniSO-8 (Plastic Micropackage) DESCRIPTION TSM1012 is a highly integrated solution for SMPS applications requiring CV (constant voltage) and CC (constant current) mode. TSM1012 integrates one voltage reference and two operational amplifiers (with ORed outputs common collectors). The voltage reference combined with one operational amplifier makes it an ideal voltage controller. The other operational, combined with few external resistors and the voltage reference, can be used as a current limiter. APPLICATIONS PIN CONNECTIONS (top view) 1 Vref 1,25V 2 3 Part Number Temperature Package Vref Range S D % TSM1012I TSM1012AI TSM1012I TSM1012AI -40 to 105°C -40 to 105°C -40 to 105°C -40 to 105°C • • • • 1 0.5 1 0.5 8 28V CC- Out CC ■ ADAPTERS ■ BATTERY CHARGERS ORDER CODE Vcc CC+ Gnd 7 6 CV Marking 4 CV- CV+ 5 M1012 M1012A M804 M805 D = Small Outline Package (SO) - also available in Tape & Reel (DT S = Small Outline Package (MiniSO8) - also available in Tape & Reel (ST) February 2004 1/8 TSM1012 PIN DESCRIPTION SO8 & MiniSO8 Pin out Name Pin # Vref CCCC+ CVCV+ Gnd Out Vcc 1 2 3 4 5 6 7 8 Type Analog Output Analog Input Analog Input Analog Input Analog Input 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 Input pin of the operational amplifier Ground Line. 0V Reference For All Voltages Output of the two operational amplifier Power supply line. ABSOLUTE MAXIMUM RATINGS Symbol Vcc Vi Tstg Tj Iref ESD Rthja Rthja DC Supply Voltage DC Supply Voltage (50mA =< Icc) Input Voltage 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 Unit -0.3V to Vz -0.3 to Vcc -55 to 150 150 2.5 2 180 175 V V °C °C mA kV °C/W °C/W Value Unit 4.5 to Vz -40 to 105 V °C OPERATING CONDITIONS Symbol Vcc Toper 2/8 Parameter DC Supply Conditions Operational temperature TSM1012 ELECTRICAL CHARACTERISTICS Tamb = 25°C and Vcc = +18V (unless otherwise specified) Symbol Parameter Test Condition Min Typ Max Unit Vcc = 18V, no load Tmin. < Tamb < Tmax. 100 180 µA Icc = 50mA 28 Tamb = 25°C Tmin. ≤ Tamb ≤ Tmax. Tamb = 25°C Tmin. ≤ Tamb ≤ Tmax. 1 Total Current Consumption Icc Total Supply Current, excluding current in Voltage Reference1). Vcc clamp voltage Vz Operators Input Offset Voltage Vio TSM1012 TSM1012A DVio 0.5 Input Offset Voltage Drift V 4 5 2 3 mV µV/°C 7 Iio Input Offset Current Tamb = 25°C Tmin. ≤ Tamb ≤ Tmax. 2 30 50 nA Iib Input Bias Current Tamb = 25°C Tmin. ≤ Tamb ≤ Tmax. 20 50 150 200 nA VCC = 4.5V to 28V SVR Supply Voltage Rejection Ration Vicm Input Common Mode Voltage Range CMR Common Mode Rejection Ratio 65 100 0 Tamb = 25°C Tmin. ≤ Tamb ≤ Tmax. 70 60 Transconduction Gain. Sink Current Only2) Tamb = 25°C Tmin. ≤ Tamb ≤ Tmax. 0.5 Low output voltage at 5 mA sinking current Output Short Circuit Current. Output to (Vcc-0.6V). Sink Current Only Tmin. ≤ Tamb ≤ Tmax. dB Vcc-1.5 V 85 dB 1 1 mA/mV Output stage Gm Vol Ios Voltage reference Vref Reference Input Voltage TSM1012 1% precision TSM1012A 0.5% precision ∆Vref Tamb = 25°C Tmin. ≤ Tamb ≤ Tmax. 6 5 10 Tamb = 25°C Tmin. ≤ Tamb ≤ Tmax. Tamb = 25°C Tmin. ≤ Tamb ≤ Tmax. 1.238 1.225 1.244 1.237 1.25 Reference Input Voltage Deviation Over Tmin. ≤ Tamb ≤ Tmax. Temperature Range RegLine Reference input voltage deviation over Vcc range. RegLoad Reference input voltage deviation over output current. 250 1.25 20 400 mV mA 1.262 1.273 1.256 1.261 V 30 mV Iload = 1mA 20 mV Vcc = 18V, 0 < Iload < 2.5mA 10 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 difference voltage 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. 3/8 TSM1012 Figure 1 : Internal Schematic Vcc 1 8 Vref 28V 1,25V CV+ CV 5 Out 7 CC+ 3 CC- 4 CC Gnd 2 CV- 6 Figure 2 : Typical Adapter or Battery Charger Application Using TSM1012 Rlimit optocoupler secondary side D2 OUT+ TSM1012 1 C4 47nF Vcc 8 R3 Vref 1,25V 28V CV+ CV 5 Out R2 Rvc1 Cvc1 22K 2,2nF 7 C3 R4 C1 PWM controller CC+ C2 R5 D1 CC 3 CC- optocoupler primary side Rsense 4 2 Gnd Ric2 1K CV- Cic1 2,2nF 6 R1 Ric1 22K OUT- In the above application schematic, the TSM1012 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. 4/8 TSM1012 PRINCIPLE OF OPERATION AND APPLICATION HINTS 1.1. Voltage Control The voltage loop is controlled via a first transconductance 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 R2 should be chosen as written in Equation 1. R1 = R2 x Vref / (Vout - Vref) Eq1 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 should be 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). Note that the Rsense resistor should be chosen taking into account the maximum dissipation (Plim) through it during full load operation. Plim = Vsense x Ilim. eq3 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-connuctance 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 1. Voltage and Current Control 1.2. 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: Rsense x Ilim = Vsense eq2 Vsense = R5*Vref/(R4+R5) Ilim = R5*Vref/(R4+R5)*Rsense eq2' where Ilim is the desired limited current, and Vsense is the threshold voltage for the current control loop. 0 TSM1012 Vcc : independent power supply Secondary current regulation Iout TSM1012 Vcc : On power output Primary current regulation 2. Compensation The voltage-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 compensation network is shown in Fig.2. It consists of a capacitor Cvc1=2.2nF and a resistor Rcv1=22KΩ in series. 5/8 TSM1012 4. Voltage clamp The following schematic shows how to realize a low-cost power supply for the TSM1012 (with no additional windings).Please pay attention to the fact that in the particular case presented here, this low-cost power supply can reach voltages as high as twice the voltage of the regulated line. Since the Absolute Maximum Rating of the TSM1012 supply voltage is 28V. In the aim to protect he TSM1012 against such how voltage values a internal zener clamp is integrated. Rlimit = (Vcc-Vz)Ivz 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 compensation network is shown in Fig.2. It consists of a capacitor Cic1=2.2nF and a resistor Ric1=22KΩ in series. 3. Start Up and Short Circuit Conditions Under start-up or short-circuit conditions the TSM1012 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 TSM1012 has to be ensured under any condition. It would then be necessary to add some circuitry to supply the chip with a separate power line. This can be achieved in numerous ways, including an additional winding on the transformer. Figure 4 : Clamp voltage cc Rlimit Vcc Vz Ivz TSM1012 28V Figure 5 : Rlimit optocoupler secondary side D2 OUT+ TSM1012 1 C4 47nF Vcc 8 R3 Vref 1,25V 28V CV+ CV 5 Out R2 Rvc1 Cvc1 22K 2,2nF 7 C3 R4 C1 PWM controller CC+ C2 R5 CC- optocoupler primary side D1 Rsense 4 CC 3 2 Gnd Ric2 1K CV- Cic1 2,2nF 6 R1 Ric1 22K OUT- 6/8 TSM1012 PACKAGE MECHANICAL DATA SO-8 MECHANICAL DATA DIM. mm. MIN. TYP inch MAX. MIN. TYP. MAX. A 1.35 1.75 0.053 0.069 A1 0.10 0.25 0.04 0.010 A2 1.10 1.65 0.043 0.065 B 0.33 0.51 0.013 0.020 C 0.19 0.25 0.007 0.010 D 4.80 5.00 0.189 0.197 E 3.80 4.00 0.150 0.157 e 1.27 0.050 H 5.80 6.20 0.228 0.244 h 0.25 0.50 0.010 0.020 L 0.40 1.27 0.016 0.050 k ddd 8˚ (max.) 0.1 0.04 0016023/C 7/8 TSM1012 PACKAGE MECHANICAL DATA 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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