TSM1011

TSM1011 Constant Voltage and Constant Current Controller for Battery Chargers and Adapters s s s s s s s 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 2 3 4 Vref CcCc+ Cv- Vcc Out 8 7 Gnd 6 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 s s Adapters Battery chargers 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 MiniSO-8 (Plastic Micropackage) D = Small Outline Package (SO) - also available in Tape & Reel (DT ST = Small Outline Package (MiniSO8) only available in Tape & Reel November 2003 Revision C 1/9 TSM1011 1 PIN DESCRIPTIONS PIN DESCRIPTIONS SO8 & MiniSO8 Pinout Name Vref CcCc+ CvCv+ Gnd Out Vcc Pin # 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. 2 ABSOLUTE MAXIMUM RATINGS DC Supply Voltage DC Supply Voltage (50mA =< Icc) Input Voltage Power dissipation 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 -55 to 150 150 10 2 180 175 Unit V V W °C °C mA KV °C/W °C/W Symbol Vcc Vi PT Tstg Tj Iref ESD Rthja Rthja 3 OPERATING CONDITIONS Parameter DC Supply Conditions Operational temperature Value 4.5 to Vz 0 to 105 Unit V °C Symbol Vcc Toper 2/9 ELECTRICAL CHARACTERISTICS 4 ELECTRICAL CHARACTERISTICS Parameter Test Condition Vcc = 18V, no load Tmin. < Tamb < Tmax. Icc = 50mA Tamb = 25°C Tmin. ≤ Tamb ≤ Tmax. Tamb = 25°C Tmin. ≤ Tamb ≤ Tmax. Tamb = 25°C Tmin. ≤ Tamb ≤ Tmax. Tamb = 25°C Tmin. ≤ Tamb ≤ Tmax. VCC = 4.5V to 28V 65 1.5 0 70 60 TSM1011 Tamb = 25°C and Vcc = +18V (unless otherwise specified) Symbol Min Typ Max 1 28 1 0.5 7 2 20 50 100 Vcc-1.5 Vcc-1.5 85 30 50 150 200 4 5 2 3 Unit mA V mV Total Current Consumption Icc Total Supply Current, excluding current in Voltage Reference. Vz Vcc clamp voltage Operators Vio Input Offset Voltage TSM1011 TSM1011A DVio Iio Iib SVR Vicm Vicm CMR Input Offset Voltage Drift Input Offset Current Input Bias Current Supply Voltage Rejection Ratio µV/°C nA nA dB V V dB 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. Tamb = 25°C Tmin. ≤ Tamb ≤ Tmax. Output stage Gm Transconduction Gain. Sink Current Only1 1 Vol Ios Low level output voltage at 10 mA sinking current Output Short Circuit Current. Output to Vcc. Sink Current Only 3.5 2.5 200 27 mA/mV 600 50 mV mA Tamb = 25°C Tmin. ≤ Tamb ≤ Tmax. Tamb = 25°C 2.519 2.532 Voltage reference Vref Reference Input Voltage, Iload=1mA TSM1011 1% precision TSM1011A 0.5% precision ∆Vref 2.545 2.545 20 2.57 2.557 30 20 10 V Reference Input Voltage Deviation Over Temperature Range Tmin. ≤ Tamb ≤ Tmax. Iload = 5mA Vcc = 18V, 0 < Iload < 10mA mV mV mV RegLine Reference input voltage deviation over Vcc range. RegLoad Reference input voltage deviation over output current. 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 Fig. 1: Internal Schematic ELECTRICAL CHARACTERISTICS 1 Vcc Vref 28V Cv+ CV 5 8 Cv3 4 7 Cc+ CC Out Gnd Cc2 6 Fig. 2: Typical Adapter Application Using TSM1011 8 1 Vcc Vref 28V R3 100 D R2 To primary IL OUT+ 5 R4 10K Cv+ CV TSM1011 CvCc+ CC 4 + 7 Rvc1 22K Cvc1 2.2nF R1 3 Out Gnd + Cc2 6 Ric1 22K Cic1 2.2nF R5 Vsense 1K Rsense IL Ric2 1K 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 Load Voltage and Current Control 5 VOLTAGE AND CURRENT CONTROL TSM1011 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: R 5 ⋅ V ref I lim = ----------------------------------------------( R 4 + R 5 ) ⋅ R sense Equation 2’ 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. R 1 = R 2 ⋅  --------------------------  V –V  out ref V ref Equation 1 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). P lim = V se nse ⋅ I lim 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. 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 5.2 Current control The current loop is controlled via the second transconductance 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 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: Vout Voltage regulation Current regulation 0 TSM1011 Vcc : independent power supply Secondary current regulation Iout R sense ⋅ I lim = V sense V ref V sense = R 5 ⋅ -------------------R 4 + R5 Equation 2 TSM1011 Vcc : On power output Primary current regulation 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. 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. Fig. 4: Schematic of compensation network 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 Cic1=2.2nF and a resistor Ric1=22KΩ in series. Vcc Rlimit D To primary OUT+ 1 DS Vcc Vref 28V Cv+ CV TSM1011 R3 100 8 R2 IL 5 R4 10K CvCc+ CC 4 + 7 Rvc1 22K Cvc1 2.2nF R1 3 Out Gnd CS + + Cc2 6 Cic1 2.2nF Ric1 22K OUT- R5 Vsense 1K Rsense IL Ric2 1K 7 START UP AND SHORT CIRCUIT CONDITIONS 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. 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 Load Voltage clamp 8 VOLTAGE CLAMP Fig. 5: Clamp voltage Vcc Rlimit Ivz TSM1011 28V Vcc Vz TSM1011 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. 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 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 8˚ (max.) 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 PACKAGE MECHANICAL DATA inch TYP. MAX. 0.069 0.010 0.065 0.020 0.010 0.197 0.157 0.050 0.244 0.020 0.050 0.04 0016023/C 8/9 PACKAGE MECHANICAL DATA 10 PACKAGE MECHANICAL DATA TSM1011 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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