TSM1011 Constant Voltage and Constant Current Controller for Battery Chargers and Adapters ■ ■ ■ ■ ■ ■ ■ Constant voltage and constant current control Low voltage operation Low external component count Current sink output stage Easy compensation 2KV ESD protection VOLTAGE REFERENCE: l Fixed output voltage reference 2.545V l 0.5% and 1% voltage precision PIN CONNECTIONS (top view) 1 Vref Vcc 8 2 Cc- Out 7 3 Cc+ Gnd 6 4 Cv- Cv+ 5 DESCRIPTION The TSM1011 is a highly integrated solution for SMPS applications requiring CV (constant voltage) and CC (constant current) modes. The TSM1011 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 amplifier, combined with few external resistors and the voltage reference, can be used as a current limiter. D SO-8 (Plastic Package) APPLICATIONS ■ ■ Adapters Battery chargers D MiniSO-8 (Plastic Micropackage) ORDER CODE Part Number TSM1011ID TSM1011AID TSM1011IS TSM1011AIS Temperature Range 0 to 0 to 0 to 0 to 105°C 105°C 105°C 105°C Package Marking S D • • • • M1011 M1011A M802 M803 D = Small Outline Package (SO) - also available in Tape & Reel (DT ST = Small Outline Package (MiniSO8) only available in Tape & Reel September 2003 Revision B 1/9 TSM1011 1 PIN DESCRIPTIONS PIN DESCRIPTIONS SO8 & MiniSO8 Pinout 2 Name Pin # Vref CcCc+ CvCv+ Gnd Out Vcc 1 2 3 4 5 6 7 8 Type Function Analog Output Analog Input Analog Input Analog Input Analog Input Power Supply Analog Output Power Supply 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 PT Toper Tstg Tj Iref ESD Rthja Rthja 3 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 Unit -0.3V to Vz -0.3 to Vcc 0 to 105 -55 to 150 150 10 2 180 175 V V W °C °C °C mA KV °C/W °C/W Value Unit 4.5 to Vz V OPERATING CONDITIONS Symbol Vcc 2/9 Value Parameter DC Supply Conditions ELECTRICAL CHARACTERISTICS 4 TSM1011 ELECTRICAL CHARACTERISTICS Tamb = 25°C and Vcc = +18V (unless otherwise specified) Symbol Parameter Total Current Consumption Icc Total Supply Current, excluding current in Voltage Reference. Vz Vcc clamp voltage Operators Vio Input Offset Voltage TSM1011 TSM1011A DVio Test Condition Min Vcc = 18V, no load Tmin. < Tamb < Tmax. Icc = 50mA Typ Max Unit 1 mA 28 Tamb = 25°C Tmin. ≤ Tamb ≤ Tmax. Tamb = 25°C Tmin. ≤ Tamb ≤ Tmax. 1 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 SVR Supply Voltage Rejection Ratio VCC = 4.5V to 28V 65 Vicm Vicm CMR Input Common Mode Voltage Range for CV op-amp Input Common Mode Voltage Range for CC op-amp Common Mode Rejection Ratio Tamb = 25°C Tmin. ≤ Tamb ≤ Tmax. 1.5 0 70 60 Output stage Gm Transconduction Gain. Sink Current Only1 Vol Ios Low level output voltage at 10 mA sinking current Output Short Circuit Current. Output to Vcc. Sink Current Only Voltage reference Vref Reference Input Voltage, Iload=1mA TSM1011 1% precision TSM1011A 0.5% precision ∆Vref Tamb = 25°C Tmin. ≤ Tamb ≤ Tmax. Tamb = 25°C Tmin. ≤ Tamb ≤ Tmax. dB Vcc-1.5 Vcc-1.5 85 V V dB 3.5 2.5 200 mA/mV 600 mV 27 50 mA 2.545 2.545 2.57 2.557 V 20 Tamb = 25°C 2.519 2.532 Reference Input Voltage Deviation Over Temperature Range Tmin. ≤ Tamb ≤ Tmax. RegLine Reference input voltage deviation over Vcc range. RegLoad Reference input voltage deviation over output current. 1 100 30 mV Iload = 5mA 20 mV Vcc = 18V, 0 < Iload < 10mA 10 mV 1) The current depends on the difference voltage beween 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 3.5mA. 3/9 TSM1011 ELECTRICAL CHARACTERISTICS 8 Fig. 1: Internal Schematic Vcc 1 Vref 28V Cv+ 5 CV Cv- 4 Out 7 Cc+ 3 CC 6 Gnd 2 Cc- 8 Fig. 2: Typical Adapter Application Using TSM1011 R3 100 Vcc 1 OUT+ R2 To primary Vref 28V 5 D TSM1011 Cv+ R4 10K Cv- Load CV IL 4 + 3 Cc+ CC Out 7 Rvc1 22K 2 Gnd R5 Vsense 1K Rsense IL 6 Cc- + Ric2 1K Ric1 Cvc1 2.2nF R1 Cic1 2.2nF 22K OUT- In the above application schematic, the TSM1011 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. 4/9 Voltage and Current Control 5 TSM1011 VOLTAGE AND CURRENT CONTROL 5.1 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 relative values of R1 and R2 should be chosen in accordance with Equation 1: V ref R 1 = R 2 ⋅ --------------------------- V –V out Equation 1 R 5 ⋅ V ref I lim = -----------------------------------------------( R 4 + R 5 ) ⋅ R sense 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. ref P lim = V se nse ⋅ I lim where Vout is the desired output voltage. To avoid discharge of the load, the resistor bridge R1, R2 should have high impedance. For this type of application, a total value of 100kΩ (or more) would be appropriate for the resistors R1 and R2. For example, if R2 = 100kΩ, Vout = 4.10V, Vref=2.5V, then R1 = 41.9KΩ. Note: If the low drop diode is to 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). 5.2 Current control The current loop is controlled via the second transconductance operational amplifier, the sense resistor Rsense, and the optocoupler. 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 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. Fig. 3: Output voltage versus output current Vout Voltage regulation Current regulation 0 TSM1011 Vcc : independent power supply Secondary current regulation Iout TSM1011 Vcc : On power output Primary current regulation R sense ⋅ I lim = V sense V ref V sense = R 5 ⋅ -------------------R 4 + R5 Equation 3 Therefore, for most adapter and battery charger applications, a quarter-watt, or half-watt resistor to make the current sensing function is sufficient. Vsense threshold is achieved externally by a resistor bridge tied to the Vref voltage reference. Its midpoint 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 in Figure 3. The resistors of this bridge are matched to provide the best precision possible. The control equation verifies that: Equation 2’ Equation 2 5/9 TSM1011 6 Compensation COMPENSATION The voltage-control transconductance operational amplifier can be fully compensated. Both its output and negative input are directly accessible for external compensation components. The current-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 Figure 5 . It consists of a capacitor Ccv1=2.2nF and a resistor Rcv1=22KΩ in series. An example of a suitable compensation network is shown in Figure 5 . It consists of a capacitor Cic1=2.2nF and a resistor Ric1=22KΩ in series. Fig. 4: Schematic of compensation network Vcc 1 OUT+ D 8 Rlimit To primary Vcc Vref R2 28V DS 5 IL R3 100 TSM1011 Cv+ R4 10K Cv- Load CV 4 + 3 Cc+ CC Cc- + R5 Vsense 1K Ric2 1K R1 Cic1 2.2nF 22K OUT- START UP AND SHORT CIRCUIT CONDITIONS Under start-up or short-circuit conditions the TSM1011 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 not considered to be precise enough for the application, then a sufficient supply for the TSM1011 has to be ensured under all conditions. This means that it is 6/9 Rvc1 Ric1 Rsense IL 7 7 22K Gnd 6 + 2 CS Out Cvc1 2.2nF 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. Voltage clamp 8 TSM1011 VOLTAGE CLAMP The schematic in Figure 5 shows how to realize a low-cost power supply for the TSM1011 (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. Fig. 5: Clamp voltage Vcc Rlimit Ivz Vcc Vz TSM1011 28V Since the Absolute Maximum Rating of the TSM1011 supply voltage is 28V. In the aim to protect he TSM1011 against such how voltage values a internal zener clamp is integrated. R limit = I vz ⋅ ( V cc – V z ) 7/9 TSM1011 9 PACKAGE MECHANICAL DATA PACKAGE MECHANICAL DATA SO-8 MECHANICAL DATA DIM. mm. MIN. MAX. MIN. 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 e TYP inch 1.27 TYP. MAX. 0.157 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 8/9 PACKAGE MECHANICAL DATA TSM1011 10 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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