november 2004 revision 1 1/10 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 description tsm1015 is a highly integrated solution for smps applications requiring cv (constant voltage) and cc (constant current) mode. tsm1015 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, combined with few external resistors and the voltage reference, can be used as a current limiter. tsm1015 is pin to pin compatible with tsm103 and represents an enhanced version low consumption. pin connections (top view) applications adapters battery chargers order codes d so-8 (plastic package) s miniso-8 (plastic micropackage) 1 2 3 45 6 cc- gnd vcc vref cc out 7 8 cc+ cv out cv- part number temperature range package packaging vref (%) marking TSM1015ID -40 to 105c so-8 tube 1 m1015 TSM1015IDt tape & reel 1 m1015 tsm1015aid tube 0.5 m1015a tsm1015aidt tape & reel 0.5 m1015a tsm1015ist mini so-8 tape & reel 1 m810 tsm1015aist tape & reel 0.5 m811 this is preliminary information on a new product now in development or undergoing evaluation. details are subject to change wit hout notice. tsm1015 low consumption voltage and current controller for battery chargers and adaptors preliminary data
tsm1015 absolute maximum ratings 2/10 1 absolute maximum ratings table 1: key parameters and their absolute maximum ratings 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 pt power dissipation w 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 table 2: operating conditions symbol parameter value unit vcc dc supply conditions 4.5 to vz v toper operational temperature -40 to 105 c table 3: pin description - so-8 and mini so-8 pin out name pin # type function cvout 1 analog output output of the operational amplifier cv- 2 analog input input pin of the operational amplifier vref 3 analog output voltage reference gnd 4 power supply ground line. 0v reference for all voltages cc+ 5 analog input input pin of the operational amplifier cc- 6 analog input input pin of the operational amplifier ccout 7 analog output output of the operational amplifier vcc 8 power supply power supply line.
electrical characteristics tsm1015 3/10 2 electrical characteristics table 4: electrical characteristics tamb = 25c 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 reference 1 . 1) test conditions: pin 6 and 4 connected to gnd, pin 2 and 1 connected to 1.25v, pin 5 connected to 200mv. vcc = 18v, no load tmin. < tamb < tmax. 100 180 a vz vcc clamp voltage icc = 50ma 28 v operator 1: op-amp with non-inverting input connected to the internal vref vref+v io input offset voltage + voltage reference tsm1015 tsm1015a t amb = 25 c t min. t amb t max. t amb = 25 c t min. t amb t max. 1.251 1.25 1.266 1.279 1.258 1.267 v dv io input offset voltage drift 7 v/ c operator 2 v io input offset voltage tsm1015 tsm1015a t amb = 25 c t min. t amb t max. t amb = 25 c t min. t amb t max. 1 0.5 4 5 2 3 mv dv io input offset voltage drift 7 v/ c i ib input bias current t amb = 25 c t min. t amb t max. 20 50 150 200 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 t min. t amb t max. 70 60 85 db output stage gm transconduction gain. sink current only 2 2) the current depends on the difference voltage between the negative and the positive inputs of the amplifier. if the voltage o n the minus input is 1mv higher than the positive amplifier, the sinking current at the output out will be increased by gm*1ma. t amb = 25 c t min. t amb t max. 0.5 1 1 ma/mv vol low output voltage at 5 ma sinking cur- rent t min. t amb t max. 250 400 mv ios output short circuit current. output to (vcc-0.6v). sink current only t amb = 25 c t min. t amb t max. 6 5 10 ma vo ltage refer ence v ref reference input voltage tsm1015 1% precision tsm1015a 0.5% precision t amb = 25 c t min. t amb t max. t amb = 25 c t min. t amb t max. 1.238 1.225 1.244 1.237 1.25 1.25 1.262 1.273 1.256 1.261 v ? v ref reference input voltage deviation over temperature range t min. t amb t max. 20 30 mv regline reference input voltage deviation over vcc range. lload = 1ma 20 mv regload reference input voltage deviation over output current. vcc = 18v, 0 < iload < 2.5ma 10 mv
tsm1015 electrical characteristics 4/10 in the above application schematic, the tsm1015 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. figure 1: internal schematic figure 2: typical adapter or battery charger application using tsm1015 28v vcc cc- cc out gnd cv- cv out vref vref 1 2 3 45 6 7 8 cc+ cc cv d r2 r1 rsense rvc1 22k cvc1 2.2nf ric1 22k cv to primary out+ out- + cic1 2.2nf load il ric2 1k r5 10k r4 100k r3 1k il vsense + 28v vcc cv- cv out gnd cc- cc+ vref 3 2 1 4 5 6 7 8 cv cc cc out tsm1015 ocp r6 1k + 47nf
principles of operation and application tips tsm1015 5/10 3 principles of operation and application tips 3.1 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 v ref / (v out - v ref ) equation 1 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 100k ? (or more) would be appropriate for the resistors r1 and r2. as an example, with r2 = 100k ? , vout = 4.10v, vref = 1.25v, then r1 = 41.9k ? . 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). 3.2 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 llim = vsense equation 2 vsense = r5*vref/(r4+r5) llim = r5*vref/(r4+r5)*rsense 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. plim = vsense x llim 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 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.
tsm1015 principles of operation and application tips 6/10 figure 3: output voltage versus output current 3.3 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=22k ? 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 compensation network is shown in fig.2. it consists of a capacitor cic1=2.2nf and a resistor ric1=22k ? in series. 3.4 start-up and short circuit conditions under start-up or short-circuit conditions the tsm1015 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 tsm1015 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. 3.5 voltage clamp the following schematic shows how to realize a low-cost power supply for the tsm1015 (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 tsm1015 supply voltage is 28v. in the aim to protect he tsm1015 against such how voltage values a internal zener clamp is integrated. rlimit = (vcc-vz)ivz vout iout voltage regulation current regulation tsm1015 vcc : independent power supply 0 secondary current regulation tsm1015 vcc : on power output primary current regulation
principles of operation and application tips tsm1015 7/10 figure 4: clamp voltage figure 5: voltage controller and over current detection schematic vz 28v vcc rlimit vcc ivz tsm1015 d r2 r1 rsense rvc1 22k cvc1 2.2nf ric1 22k cv to primary out+ out- + cic1 2.2nf load il ric2 1k r5 10k r4 100k r3 1k il vsense + 28v vcc cv- cv out gnd cc- cc+ vref 3 2 1 4 5 6 7 8 cv cc cc out tsm1015 ocp r6 1k
tsm1015 package mechanical data 8/10 4 package mechanical data dim. mm. inch min. typ 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 ? (max.) ddd 0.1 0.04 so-8 mechanical data 0016023/c 8
package mechanical data tsm1015 9/10 package mechanical data
tsm1015 revision history 10/10 5 revision history date revision description of changes 01 nov 2004 1 first release information furnished is believed to be accurate and reliable. however, stmicroelectronics assumes no responsibility for the co nsequences 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 publicati on are subject to change without notice. this publication supersedes and replaces all information previously supplied. stmicroelectronics prod ucts are not authorized for use as critical components in life support devices or systems without express written approval of stmicroelectro nics. the st logo is a registered trademark of stmicroelectronics all other names are the property of their respective owners ? 2004 stmicroelectronics - all rights reserved stmicroelectronics group of companies australia - belgium - brazil - canada - china - czech repubic - finland - france - germany - hong kong - india - israel - italy - japan - malaysia - malta - morocco - singapore - spain - sweden - switzerland - united kingdom - united states of america www.st.com
|
