TSM1012AI

TSM1012AID STMICROELECTRONICS | Alldatasheet

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Technical content

I CONSTANT VOLTAGE AND CONSTANT CURRENT CONTROL I LOW CONSUMPTION I LOW VOLTAGE OPERATION I LOW EXTERNAL COMPONENT COUNT I CURRENT SINK OUTPUT STAGE I EASY COMPENSATION I HIGH AC MAINS VOLTAGE REJECTION VOLTAGE REFERENCE I FIXED OUTPUT VOLTAGE REFERENCE 1.25V I 0.5% AND 1% VOLTAGE PRECISION

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

D = Small Outline Package (SO) - also available in Tape & Reel (DT S = Small Outline Package (MiniSO8) - also available in Tape & Reel (ST) PIN CONNECTIONS (top view) Part Number Temperature Range Package Vref Marking SD% TSM1012I -40 to 105°C • 1 M1012 TSM1012AI -40 to 105°C • 0.5 M1012A TSM1012I -40 to 105°C • 1M 8 0 4 TSM1012AI -40 to 105°C • 0.5 M805 D SO-8 (Plastic Package) S MiniSO-8 (Plastic Micropackage) 28V Vref Vcc CC CC- CC+ Gnd CV CV- CV+ Out 1,25V February 2004 TSM1012 LOW CONSUMPTION VOLTAGE AND CURRENT CONTROLLER FOR BATTERY CHARGERS AND ADAPTORS

SO8 & MiniSO8 Pin out ABSOLUTE MAXIMUM RATINGS OPERATING CONDITIONS Name Pin # Type Function Vref 1 Analog Output Voltage Reference CC- 2 Analog Input Input pin of the operational amplifier CC+ 3 Analog Input Input pin of the operational amplifier CV- 4 Analog Input Input pin of the operational amplifier CV+ 5 Analog Input Input pin of the operational amplifier Gnd 6 Power Supply Ground Line. 0V Reference For All Voltages Out 7 Analog Output Output of the two operational amplifier Vcc 8 Power Supply Power supply line. Symbol DC Supply Voltage Value Unit Vcc DC Supply Voltage (50mA =< Icc) -0.3V to Vz V Vi Input Voltage -0.3 to Vcc V Tstg Storage temperature -55 to 150 °C Tj Junction temperature 150 °C Iref Voltage reference output current 2.5 mA ESD Electrostatic Discharge 2 kV Rthja Thermal Resistance Junction to Ambient Mini SO8 package 180 °C/W Rthja Thermal Resistance Junction to Ambient SO8 package 175 °C/W Symbol Parameter Value Unit Vcc DC Supply Conditions 4.5 to Vz V Toper Operational temperature -40 to 105 °C

ELECTRICAL CHARACTERISTICS

Tamb = 25°C and Vcc = +18V (unless otherwise specified) Symbol Parameter Test Condition Min Typ Max Unit Total Current Consumption Icc Total Supply Current, excluding current in Voltage Reference1). 1. Test conditions: pin 2 and 6 connected to GND, pin 4 and 5 connected to 1.25V, pin 3 connected to 200mV. Vcc = 18V, no load Tmin. < Tamb < Tmax. 100 180 µA Vz Vcc clamp voltage Icc = 50mA 28 V Operators Vio Input Offset Voltage TSM1012 TSM1012A Tamb = 25°C Tmin. ≤ Tamb ≤ Tmax. Tamb = 25°C Tmin. ≤ Tamb ≤ Tmax. 0.5 mV DV io Input Offset Voltage Drift 7 µV/°C Iio Input Offset Current T amb = 25°C Tmin. ≤ Tamb ≤ Tmax. 23 0 nA Iib Input Bias Current T amb = 25°C Tmin. ≤ Tamb ≤ Tmax. 150 200 nA SVR Supply Voltage Rejection Ration V CC = 4.5V to 28V 65 100 dB Vicm Input Common Mode Voltage Range 0 Vcc-1.5 V CMR Common Mode Rejection Ratio T amb = 25°C Tmin. ≤ Tamb ≤ Tmax. 85 dB Output stage Gm Transconduction Gain. Sink Current Only2) 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. Tamb = 25°C Tmin. ≤ Tamb ≤ Tmax. 0.5 mA/mV Vol Low output voltage at 5 mA sinking current Tmin. ≤ Tamb ≤ Tmax. 250 400 mV Ios Output Short Circuit Current. Output to (Vcc-0.6V). Sink Current Only Tamb = 25°C Tmin. ≤ Tamb ≤ Tmax. 10 mA Voltage reference Vref Reference Input Voltage TSM1012 1% precision TSM1012A 0.5% precision Tamb = 25°C Tmin. ≤ Tamb ≤ Tmax. Tamb = 25°C Tmin. ≤ Tamb ≤ Tmax. 1.238 1.225 1.244 1.237 1.25 1.25 1.262 1.273 1.256 1.261 V ref Reference Input Voltage Deviation Over Temperature Range Tmin. ≤ Tamb ≤ Tmax. 20 30 mV RegLine Reference input voltage deviation over Vcc range. Iload = 1mA 20 mV RegLoad Reference input voltage deviation over output current. Vcc = 18V, 0 < Iload < 2.5mA 10 mV

1. Voltage and Current Control 1.1. Voltage Control The voltage loop is controlled via a first transcon- ductance operational amplifier, the resistor bridge R1, R2, and the optocoupler which is directly con- nected 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 resis- tor bridge to avoid current flowing from the load through the resistor bridge, this drop should be taken into account in the above calculations by re- placing Vout by (Vout + Vdrop). 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 re- sistor bridge tied to the Vref voltage reference. Its middle point is tied to the positive input of the cur- rent 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 re- sistors 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. 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-con- nuctance operational amplifiers are common (to the output of the IC). This makes an ORing func- tion which ensures that whenever the current or the voltage reaches too high values, the optocou- pler is activated. The relation between the controlled current and the controlled output voltage can be described with a square characteristic as shown in the fol- lowing V/I output-power graph. Figure 3 : Output voltage versus output current 2. Compensation The voltage-control trans-conductance operation- al 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. Vout Iout Voltage regulation Current regulation TSM1012 Vcc : independent power supply

0 Secondary current regulation

TSM1012 Vcc : On power output Primary current regulation TSM1012 PRINCIPLE OF OPERATION AND APPLICATION HINTS

DIM. mm. inch 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 ˚ (max.) ddd 0.1 0.04 SO-8 MECHANICAL DATA 0016023/C

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