Description

The microcircuits are designed for constructing galvanically isolated converters with feedback (flyback converters) with constant Uin from 35 to 400 V (variable Uin from 85 to 300 V), Uout from 2.5 to 150 V and currents up to 30 A. Current stabilization mode and controlled current limitation, auto-restart and soft start functions, protection against overvoltage and overload, the possibility of external synchronization and shutdown control - allow you to design compact and highly reliable power supplies with an efficiency of up to 90%. In table 1 provides the main characteristics of VIPer microcircuits from STMicroelectronics.

Table 1. Main characteristics of VIPer chips from STMicroelectronics

In the recent past, many manufacturing companies began to abandon transformer power supplies due to their considerable weight and significant overall dimensions. Imagine a transformer power supply with an output power of 100-150 W, even made on a toroidal magnetic core. The mass of such a power supply will be approximately 5-7 kg, and there is nothing to even talk about its dimensions. With the advent of all kinds of PWM controller microcircuits and high-voltage powerful MOSFET transistors, transformer power supplies were replaced by pulsed ones, therefore, the overall dimensions and weight of power supplies decreased several times. Switching power supplies are not inferior to transformer ones in power, moreover, they are much more efficient. The efficiency of modern switching power supplies reaches 95%. However, such power supplies have their drawbacks: 2. Difficulty in setting up due to the selection of passive components in the PWM controller harness, in the protection circuit, etc. These shortcomings also create inconvenience when diagnosing faults and eliminating them. The main components of the classical circuit of a switching flyback power supply consist of the following blocks. 1. Input circuit (includes mains filter, diode bridge and filter capacitors). 2. PWM controller. 3. Protection circuits (overvoltage, overtemperature, etc.) 4. Output voltage stabilization circuits. 5. Powerful output MOSFET transistor. 6. Output circuit consisting of a diode bridge and filter capacitors. As you can see, the number of active components included in a switching power supply reaches several dozen, which increases the overall dimensions of the device and, as a result, creates a number of problems during design and debugging. STMicroelectronics, having analyzed the difficulties encountered when designing switching power supplies, has developed a unique series of microcircuits, combining a PWM controller, protection circuits and a powerful output MOSFET transistor on one chip. The series of devices was named VIPer. The name VIPer comes from the manufacturing technology of the MOSFET transistor itself, namely, Vertical Power MOSFET. The functional diagram of one of the devices of the VIPer family is presented in Figure 1. Rice. 1. Key Features: adjustable switching frequency from 0 to 200 kHz; current regulation mode; soft start; AC power consumption less than 1 W in standby mode; shutdown when the supply voltage drops in the event of a short circuit (short circuit) or overcurrent; trigger circuit integrated into the chip; automatic restart; overheat protection; adjustable current limit. An example of a schematic diagram of a standard connection of one of the representatives of the VIPer family is presented in Figure 2. As in similar microcircuits for constructing switching power supplies produced by companies such as Power Integrations and Fairchild, the VIPer family of microcircuits uses a current regulation mode. Two feedback loops are used - an internal current control loop and an external voltage control loop. When the MOSFET is turned on, the transformer primary current value is monitored by the SenseFET and converted to a voltage proportional to the current. When this voltage reaches a value equal to Vcomp (the voltage at the COMP pin (see Fig. 1) is the output voltage of the error amplifier), the transistor turns off. Thus, the external voltage control loop is determined by the value at which the internal current loop turns off the high-voltage switch. It is important to note one more feature of VIPer microcircuits, which puts them at a level above their competitors. This is the ability to operate at frequencies reaching 300 kHz. It allows for even greater efficiency and the use of smaller transformers, leading to miniaturization of the power supply while maintaining the design output power. Rice. 2. The VIPer family has a wide range of devices that make it easy to select a microcircuit that meets the specified technical conditions. Currently available devices, including new products, are presented in Table 1. Table 1. Summary table of VIPer family devices Name U si, V Ucc max, V R si, Ohm I s min, A F sw, kHz Frame VIPer12AS 730 38 30 0,32 60 SO-8 VIPer12ADIP 730 38 30 0,32 60 DIP-8 VIPer22AS 730 38 30 0,56 60 SO-8 VIPer22ADIP 730 38 30 0,56 60 DIP-8 VIPer20 620 15 16 0,5 up to 200 PENTAWATT H.V. VIPer20(022Y) 620 15 16 0,5 up to 200 PENTAWATT H.V. VIPer20DIP 620 15 16 0,5 up to 200 DIP-8 VIPer20A 700 15 18 0,5 up to 200 PENTAWATT H.V. VIPer20A(022Y) 700 15 18 0,5 up to 200 PENTAWATT H.V. VIPer20ADIP 700 15 18 0,5 up to 200 DIP-8 VIPer20ASP 700 15 18 0,5 up to 200 PowerSO-10 VIPer50 620 15 5 1,5 up to 200 PENTAWATT H.V. VIPer50(022Y) 620 15 5 1,5 up to 200 PENTAWATT H.V. VIPer50A 700 15 5,7 1,5 up to 200 PENTAWATT H.V. VIPer50A(022Y) 700 15 5,7 1,5 up to 200 PENTAWATT H.V. VIPer50ASP 700 15 5,7 1,5 up to 200 PowerSO-10 VIPer53DIP 620 17 1 1,6 up to 300 DIP-8 VIPer53SP 620 17 1 1,6 up to 300 PowerSO-10 VIPer53EDIP 620 17 1 1,6 up to 300 DIP-8 VIPer53ESP 620 17 1 1,6 up to 300 PowerSO-10 VIPer100 700 15 2,5 3 up to 200 PENTAWATT H.V. VIPer100(022Y) 700 15 2,5 3 up to 200 PENTAWATT H.V. VIPer100A 700 15 2,8 3 up to 200 PENTAWATT H.V. VIPer100A(022Y) 700 15 2,8 3 up to 200 PENTAWATT H.V. VIPer100ASP 700 15 2,8 3 up to 200 PowerSO-10 VIPer chips are available in various package designs, shown in Figure 3. Rice. 3. The PowerSO-10 package is a development of ST Microelectronics. This package is designed for surface mounting on a copper pad on the surface of a printed circuit board connected to the drain of a power transistor. Table 2 presents recommendations from STMicroelectronics for replacing similar devices from other manufacturers with devices from the VIPer family. This table was compiled from materials provided by STMicroelectronics. The VIPer devices listed in the table are not pin-to-pin analogues of devices from other manufacturers. The data were compiled based on similar parametric features. LNK562P — VIPER12ADIP LNK562G — VIPER12AS LNK563P — VIPER12ADIP LNK564P — VIPER12ADIP LNK564G — VIPER12AS TNY274G — VIPER12AS VIPER22AS TNY275P — VIPER12ADIP VIPER22ADIP TNY275G — VIPER12AS VIPER22AS TNY276P — VIPER12ADIP VIPER22ADIP TNY276G — VIPER12AS VIPER22AS TNY277P — VIPER12ADIP VIPER22ADIP TNY277G — VIPER12AS VIPER22AS TNY278P — VIPER22ADIP VIPER53EDIP TNY278G — VIPER22AS VIPER53ESP TNY279P — VIPER22ADIP VIPER53EDIP TNY279G — VIPER22AS VIPER53ESP TNY280P — VIPER22ADIP VIPER53EDIP TNY280G — VIPER22AS VIPER53ESP TOP232P FSDM311 FSQ0165RN FSQ311 VIPer22ADIP VIPer20ADIP TOP232G — VIPer22AS VIPer20ADIP TNY264P FSD210B FSQ510 FSQ510H VIPer12ADIP TNY264G — VIPer12AS TNY266P FSDM311 FSQ0165RN FSQ311 VIPer22ADIP VIPer20ADIP TNY266G FSDM311L VIPer22AS VIPer20ASP TNY267P FSDH0170RNB FSDL0165RN FSQ0165RN FSQ0170RNA VIPer22ADIP VIPer20ADIP TNY267G FSDL0165RL VIPer22AS VIPer20ASP TNY268P FSDH0265RN FSDH0270RNB FSDM0265RNB FSQ0265RN FSQ0270RNA VIPer22ADIP VIPer20ADIP TNY268G — VIPer22AS VIPer20ASP TNY253P — VIPer12ADIP TNY253G — VIPer12AS TNY254P — VIPer12ADIP TNY254G — VIPer12AS TNY255P — VIPer12ADIP TNY255G — VIPer12AS TNY256P FSDM311 FSQ0165RN FSQ311 VIPer22ADIP VIPer20ADIP TNY256G — VIPer22AS VIPer20ASP TNY256Y — VIPer20A TOP221P — VIPer12ADIP TOP221G — VIPer12AS TOP221Y — VIPer12ADIP TOP222P FSDM311 FSQ0165RN FSQ311 VIPer22ADIP VIPer20ADIP TOP222G — VIPer22AS VIPer20ASP TOP222Y — VIPer20A TOP223P FSDL0165RN FSQ0165RN VIPer50A TOP223G — VIPer50ASP TOP223Y — VIPer50A TOP224P FSDH0265RN FSQ0265RN VIPer50A TOP224G — VIPer50ASP TOP224Y KA5H0280RYDTU KA5M0280RYDTU VIPer50A TOP226Y KA5H0365RYDTU KA5H0380RYDTU KA5L0365RYDTU KA5L0380RYDTU KA5M0365RYDTU KA5M0380RYDTU VIPer100A TOP227Y — VIPer100A TOP209P FSDM0565RBWDTU VIPer12ADIP TOP209G — VIPer12AS TOP210PFI — VIPer12ADIP TOP210G — VIPer12AS TOP200YAI — VIPer22ADIP VIPer20A TOP201YAI — VIPer50A TOP202YAI — VIPer50A TOP203YAI — VIPer100A TOP214YAI — VIPer100A TOP204YAI — VIPer100A Rice. 4. In conclusion, I would like to note that STMicroelectronics provides developers with a package of free software for calculating the parameters of a power supply based on chips from the VIPer family. The VIPer Design Software package has an accessible and intuitive interface that allows you to set any of the necessary parameters and receive a ready-made diagram with a list of components used, graphs and oscillograms of processes. For technical information, ordering samples and delivery, please contact COMPEL. E-mail: EEPROM in a new miniature package In March 2007, STMicroelectronics announced the release of familiar EEPROM chips (capacity from 2 to 64 kBit; with SPI or I 2 C interface) in a miniature 2x3 mm MLP8 (ML - Micro Leadframe) design. In terms of its performance characteristics, the new development is comparable to its predecessor, a 4x5 mm microcircuit (in the S08N package), however, it can significantly save space on the printed circuit board, as well as reduce the cost of the final device. STMicroelectronics is the first company to bring to market a complete line of EEPROM series in such a small package. A super-thin case (only 0.6 mm) with flat pins located on both sides, the number of memory cycles up to 1 million (!), the ability to store the necessary data for more than 40 years - all this makes the microcircuit a worthy representative of its family. The new development is intended for applications in wide areas of modern microelectronics: digital photo and video cameras, miniature MP3 players, various remote controls, game consoles, wireless devices, Wi-Fi systems. The release of the new microcircuit is scheduled for the second half of 2007, but samples can be ordered now.

It is difficult to imagine a modern office without office equipment. Numerous electrical appliances have become a part of our everyday life and have become simply irreplaceable. And almost every one of these devices, be it a computer or a printer, a TV or a mobile phone charger, contains switching power supplies. Advances in microelectronics in recent years have made it possible to use pulsed sources not only in the domestic, but also in the industrial, military and medical fields. The numerous advantages of switching power supplies have long been appreciated. There are also disadvantages: pulse stabilizers often fail and do not want to start after repair. Many problems are associated with the large number of discrete components used and the difficulties in designing and manufacturing effective protection and control circuits. All these problems are solved by the VIPer family of microcircuits developed by STMicroelectronics, which are a high-voltage MOSFET transistor with a control and protection circuit in one package.

Rice. 1. Block diagram of PWM controllers of the VIPer family

Rice. 2. Circuit design of a power supply based on VIPer100

Key Features

Table 2. Comparative characteristics of VIPer and TOPSwitch

Viktor Petrovich Oleynik,

technical specialist SEA - Electronics,

Recently, incandescent lamps, which have a very limited resource of about 1000 hours, and gas-discharge lighting lamps with a resource of approximately 20,000 hours, are being vigorously replaced by LED analogues, which can function without replacement for much longer - 100,000 hours. They have the highest efficiency of converting electrical energy into light among artificial light sources, which forces the governments of many countries, including Russia, to more vigorously introduce energy-saving technologies in lighting technology. This is also facilitated by the steady decline in the cost of ultra-bright LEDs due to competition from global manufacturers.

Unfortunately, most household LED lamps use simple mains power supplies with a ballast capacitor. And this is despite the fact that the well-known disadvantages of the latter (current surge when turned on, a narrow range of mains voltage corresponding to the permissible current limits through LEDs, as well as the possibility of damage due to load breaks) lead to premature failure of the lamps. This means that such a circuit solution, in principle, cannot ensure effective long-term operation of LED light sources with an expected resource of 100,000 hours.

The proposed design of a simple, small-sized network SMPS for an LED lamp (Fig. 1) is free from such shortcomings and, despite its high operational reliability, is very cheap (about 50 rubles without LEDs). The use of computer-aided design tools for this device allows the radio amateur to independently vary the range and number of connected LEDs.
The operation of such a pulse step-down voltage stabilizer and the physical principles of its operation are described in (Fig. 1c and Fig. 2.6).
Therefore, we will take a closer look at the sequence of designing a network converter to power 17 ultra-bright LEDs used in the described device (Fig. 1). Among them are EL1-EL8 – standard 5 mm LEDs LC503TWN1-15G and EL9-EL11 – ARL-5060WYC chip LEDs, 3 pcs each. in a rectangular PLCC6 package with dimensions of 5x5 mm with a permissible forward current of up to 40 mA and a forward voltage drop of approximately 3.2 V on each diode. This choice of LEDs in the author’s copy is due to the need to illuminate the computer keyboard. The first LEDs have a small radiation angle - 15° at half power level, the second - a large one - 120°. As a result, there will be no sharp boundaries in the total light spot, and the illumination in the center is greater than at the periphery. The color shade of such a light source is average between cold and warm white, which is determined by the parameters of the LEDs used.
For design reasons, the same type of LEDs are connected in series, resulting in the ones shown in Fig. 1 two circuits (of 8 and 9 LEDs, respectively), which are connected in parallel through current-limiting resistors R2 and R3. The output voltage of the converter for both circuits is selected at 32 V with a load current of 40 mA.
To design the converter, the Non-Isolated VIPer Design Software v.2.3 (NIVDS) program was used, which is described in the article. The network voltage interval was left selected by the program by default 88...264 V. The PHI controller was used - VIPer22A chip with a conversion frequency of 60 kHz, intermittent conversion mode (DCM - Discontinuous Current Mode), output voltage - 32 V at a current of 40 mA. The inductance of storage choke L1, calculated by the program, was 2.2 mH. Other parameters of the converter: efficiency - 74%, maximum current amplitude of the switching transistor of the DA1 microcircuit - 169 mA, its maximum temperature - 47 ° C, effective value of the current consumption - 17 mA at a maximum mains voltage of 264 V.
Choke L1 is a modified high-frequency DM-0.1 500 μH. To increase its inductance to 2.2 mH, 2 layers of 100 turns of PEV-2 wire with a diameter of 0.12 mm are added to the existing winding, without changing the winding direction. The insulation between the added layers, as well as the general covering of the throttle, is done with adhesive tape. The inductor leads are bent for mounting on a printed circuit board no closer than 5 mm from the ferrite body, otherwise the factory winding leads will be damaged. Instead of the modified DM-0.1 inductor, you can use the KIG-0.2-2200 or SDR1006-2200 inductors.

A drawing of the converter printed circuit board, made of one-sided foil-coated fiberglass laminate with a thickness of 1...1.2 mm, is shown in Fig. 2, and its appearance is shown in Fig. 3. Capacitor C1 is soldered with a gap of 7...8 mm to the board, since it must be tilted towards the center of the board so that it fits into the used base from a burnt-out energy-saving lamp.

The converter can use imported oxide capacitors with a maximum operating temperature of 105 °C. Capacitors C2 and C5 are film or ceramic with a rated voltage of at least 50 V. Fusible jumper FU1 is a wire from a fuse with a rated current of 1 A. The slot protects the board if FU1 burns out. But the slot is not needed if the jumper is replaced with a fusible link in a ceramic housing (from the VP1-1, VP1-2 series) or with a safety resistor R1-25 (or a similar imported resistance of 8 ... 10 Ohms). If a safety resistor is used, the resistance of resistor R1 is reduced to 10...12 Ohms.

The LED load R2R3EL1 – EL11 is mounted on another printed circuit board made of double-sided foil fiberglass laminate with a thickness of 0.5... 1 mm (Fig. 4). The polygonal foil section in the center of the board is designed to remove heat from the EL9-EL11 surface mount LEDs. Current-limiting resistors R2 and R3 are PH1-12 of standard size 1206. The two boards are connected to each other by soldering in the corresponding contact pads three pieces of copper wire with a diameter of 0.7 mm and a length of approximately 7 mm, onto which pieces of hollow plastic rods from ball bearings are placed as limiting axle boxes handles Two wires supply power to the board with LEDs, and the third provides the necessary rigidity of the structure. When connecting, adjacent sides are those free from elements on both boards. Short pieces of wire are inserted into the holes of the contact pads marked with asterisks and soldered on both sides. First, using LATR, it is advisable to verify the stability of the output voltage of 32 V throughout the entire range of changes in the mains voltage (88 ... 264 V), while instead of LEDs, resistors with a total resistance of 800 Ohms are connected. Then the LEDs are installed in place, and instead of constant current-limiting resistors R2 and R3 is temporarily soldered with trimmers with a resistance of 150 Ohms. When taking measurements, beware of electric shock, since all elements of the device are galvanically connected to the power supply network. All changes are made only in the disabled state. Trimmer resistors are adjusted with a dielectric screwdriver. The current through each LED circuit is monitored with a milliammeter. Although the LEDs used allow forward current up to 40 mA with a corresponding increase in brightness, in order to achieve the stated durability of the LEDs, the current is set to 20 mA by adjusting the resistors. Approximately 5 minutes after switching on, the thermal conditions of the LEDs stabilize, so additional current adjustment is necessary. If there is one milliammeter, the current in each LED circuit is adjusted in turn. Finally, the tuning resistors are replaced with constants of the found resistance.

Using the Waveforms tool, the NIVDS program allows you to simulate the modes of a PHI controller. In Fig. Figure 5 shows a diagram of the pulse current in the controller at a mains voltage of 220 V, which practically coincides with the results of control measurements. The interval O...1.5 μs corresponds to the open state of the switching transistor of the DA1 microcircuit (forward stroke of the converter). The blue color shows a graph of the current in the storage choke during the reverse stroke of the converter. The interval of 1.5 ... 13 μs corresponds to the stage of transferring to the load the energy accumulated by the throttle during forward stroke. The interval of 13...16.6 μs is the so-called dead pause in the operation of the converter, when free damped oscillations of voltage and current occur in the output circuit. These oscillations are more clearly illustrated by a diagram of the voltage at the source of the transistor relative to the common power wire (Fig. 6), where it is clearly visible that damped voltage oscillations occur relative to the level of 32 V, corresponding to the output voltage of the converter. The C4C5 output filter reduces output voltage ripple to 300 mV.

As can be seen from Fig. 5 and 6, the peak current of the switching transistor of the microcircuit (169 mA) is several times less than the maximum permissible value of 700 mA, the voltage at the drain of this transistor (300 V) is also less than the maximum permissible 730 V. This ensures operation of the converter with a large margin of electrical strength, which, along with with thermal protection built into the chip, as well as protection against short circuits and breaks in the load, guarantees many years of reliable operation of the described device.

The appearance of the LED lamp is shown in Fig. 7. It uses a reflector from a faulty flashlight.

Literature
1. Kosenko S. Features of the operation of inductive elements in single-cycle converters. - Radio. 2005. No. 7. p. 30-32.
2. Kosenko S. Automated design of small-sized SMPS on VIPer microcircuits - Radio, 2008, No. 5, p. 32. 33.

The implementation of many functions of modern household appliances is largely based on the use of microcontrollers and additional circuits. Although conventional iron-core transformers can provide isolation from the AC mains, low-voltage power supplies to microprocessors whose outputs control grid-connected power switches require another layer of electrical isolation, such as optocouplers or switching transformers.

Designers can avoid the hassle and expense of adding additional insulation components to an uninsulated AC line. But if obtaining one low voltage using an autonomous switching power supply does not cause any difficulties, obtaining several voltages presents a certain problem and requires a relatively complex design.

As an alternative, you can use a single-chip switching converter controller, such as the one produced (IC 1 in Figure 1), with which you can create two stabilized voltages with a total power of up to 3.3 W from an AC mains voltage of 88 V to 265 V. . With the component ratings indicated in the figure, the circuit provides a load with voltages of -5 V ±5% at a current of up to 300 mA and -12 V ±10% at a current of up to 150 mA.

The Viper22A includes a 60 kHz clock generator, a voltage reference, thermal protection circuitry, and a high-voltage power MOSFET capable of dissipating several watts of power. Although the Viper22A is available in an 8-pin package, it requires only four pins to operate: the VDD input, the FB feedback input, and the MOSFET source and drain pins. The remaining pins - the backup power input and additional drain contacts - serve to improve heat dissipation into the printed circuit board.

Resistor R 4 limits input current surges and at the same time serves as a protective fuse. With diode D 1, the alternating voltage of the network is rectified to an effective value of about 160 V and smoothed by a filter on elements C 1, R 1, L 1, and C 2. In addition to smoothing DC ripple, the filter reduces electromagnetic interference to a level that meets the requirements of the European standard 55014 CISPR14. An additional reduction in conducted emissions is provided by damping capacitor C 9, connected in parallel with diode D 1.

Capacitor C 3 accumulates positive charge during the time when the MOSFET is closed, and releases it to supply voltage V DD to IC 1 when the MOSFET is open. The reverse voltage of a D 3 diode can reach the sum of the peak rectified mains voltage and the maximum output DC voltage, so a fast recovery diode rated at 600 V peak reverse voltage should be selected as a D 3 diode.

For feedback that closes the control loop, voltage V OUT2 is used. The sum of the base-emitter voltage of the PNP general purpose transistor Q 1 and the reverse voltage of the zener diode D 6 sets the voltage V OUT2 equal to -5 V. The zener diode D 7 shifts the voltage at the feedback input of the microcircuit IC 1 into its linear range of 0 ... 1 V. To eliminate high-frequency To generate generation in the feedback circuit, the conductors going to the capacitor C 4 must be made as short as possible. The two windings of coil L2 are wound on a TDK SRW0913 dumbbell ferrite core; The ratio of winding turns determines the output voltage V OUT1. To maintain stabilization when there is no load at the V OUT1 output and full load at V OUT2, an additional resistor R 5 is connected between V OUT1 and the common ground line.