Today, conventional cam switches, limit switches, and other electrical and mechanical devices are continuously being eliminated in home appliances and other application technologies that supply loads from alternating current, and are replaced by electronic controllers. In general, this controller is based on a low-cost microcontroller and needs to be powered by a 5V supply. Currently, there are many low-current 5V power regulators on the market, but most controllers require that the AC voltage be converted to a lower voltage DC voltage before adjusting the DC voltage to 5V.
ST recently introduced VB409 regulator, its design can be rectified 110/230Vrms AC directly connected to the output voltage is stable at 5V ± 5%, the internal output current is limited to 80mA. At present, there are many high-voltage linear voltage regulators of other brands that can be directly connected to the rectified AC power. However, the VB409 based on the conduction angle limiting technology can greatly improve the device efficiency and power supply capability by adopting a controller technology. The VB409 output current is three times that of standard high-voltage linear regulators, making it particularly suitable for low-cost, low-power applications such as washing machines, central heating, power metering and similar applications that do not require galvanic isolation. The VB409 is highly efficient and has low internal power consumption. The package can use Surface Mount Technology PowerSO10(TM) or PENTAWATTHV (high voltage version) with through-hole mounting technology.
Manufacturing process and conduction angle control technology are two main features of VB409. This device is manufactured using the patented VIPowerM1 smart power technology developed by ST. In addition, ST also has multiple “vertical smart power†technologies. In this technology, a high-intensity bipolar or DMOS vertical power supply stage (current image In the discrete power transistor, the same DC body silicon) as the analog and digital circuits on the chip provide control, diagnostic and protection functions.
This technology started as large-scale production as early as the 1990s and has been widely used in the automotive field. Compared with automobiles and home appliances, the application environment is even worse, which proves the reliability of the technology. In addition to its inherent reliability, the number of external components required by the VB409 is also reduced, which further improves the overall reliability of the system.
The second feature of the VB409 is the technique it uses to convert the rectified AC input voltage to a 5V output voltage. Internal power consumption determines the maximum current that can be supplied without a heatsink, or the size of the heatsink required to supply a specified output current (the corresponding cost). Therefore, various voltage regulators are designed. An important issue to pay attention to. In offline regulator technology, the input is the AC supply voltage, but the output voltage is very low, only a few volts, the huge differential pressure between the input and output means that the efficiency is particularly important.
The VB409 has two separate stages, each connected to an external capacitor for storing electrical energy. The first stage is a pre-regulator, which is responsible for reducing the rectified high-voltage power supply to low voltage while charging the capacitor. The capacitor stores power during each AC power cycle, and then powers the second stage, low voltage linear regulator.
The pre-regulator uses a bipolar "Trilinton" passive device and three comparators. The first comparator measures the voltage on the integrated resistor and performs the internal current limiting function; the second comparator is responsible for the divided voltage of the rectified power input (determined by the external resistor divider) and the preset reference voltage In contrast, the third one is responsible for detecting the voltage on the capacitor. When the voltage at the midpoint of the resistor divider is below the threshold (eg, the conduction angle is less than the cutout value), the internal limiting current charges the capacitor. After the voltage on the capacitor reaches the maximum internal fixed value, the third comparator immediately acts to limit the current to the load requirement. When the conduction angle limit is reached, the input voltage level is switched to a high-impedance state, stopping the power absorption from the power supply. Since the VB409 only draws power from the power supply during the low-voltage portion of each positive cycle, the first-level power consumption is greatly reduced compared to the topology technology that continuously draws power from the power supply.
Of course, in order to ensure proper operation of the VB 409, the external capacitor must be charged during charging, and can be supplied to the second stage when offline. To ensure the functionality of the second stage at the maximum output current value, when selecting the capacitor value, the voltage on the capacitor must be greater than the rated minimum value, which is the sum of the output voltage and the minimum voltage drop on the second stage. Important parameters include the capacitance of the external capacitor and the ratio of the resistor divider. This topology allows the designer to use the capacity and cost of the external capacitor to solve the power consumption problem (heat sink volume and cost).
The maximum value of the external capacitor pre-regulator is 16V (typical). This pre-regulator can also supply the second load (such as a relay) that does not require excessive voltage regulation. Therefore, the VB409 can also be called double. Output regulator.
In a linear regulator, for a specified output voltage, the internal power dissipation is a function of the average input voltage: Pdiss = Iout(Vin - Vout), where Vin represents the average input voltage over a full cycle of the AC power supply. average value. For the VB409, as long as the preset conduction angle is exceeded (for most parts of the current cycle), the input current is negligible, and accordingly, the power consumption is correspondingly greatly reduced.
For example, when the average input voltage is 175V (equivalent to a 230V European grid power supply) and the output current is 25mA, the internal power dissipation should be (175-5) x 0.025 approximately equal to 4.4W when using a standard voltage regulator. With a VB409, an external 100uF capacitor, and a resistor divider ratio that guarantees correct operation, the internal power dissipation measurement is only 0.9W, which is even lower than one-quarter of the normal value!
Inductor and output pin in series, as shown in Figure 3, can further reduce the VB409's power consumption.
The series inductance removes the power switch coupling from the power supply, allowing the switch to operate in the saturation region when it is turned on. With this configuration, power consumption is reduced by 25% compared to a standard topology without an inductor. Diode D creates a discharge path for the energy stored in the inductor, limiting the overvoltage on the device when it is turned off.
ST recently introduced VB409 regulator, its design can be rectified 110/230Vrms AC directly connected to the output voltage is stable at 5V ± 5%, the internal output current is limited to 80mA. At present, there are many high-voltage linear voltage regulators of other brands that can be directly connected to the rectified AC power. However, the VB409 based on the conduction angle limiting technology can greatly improve the device efficiency and power supply capability by adopting a controller technology. The VB409 output current is three times that of standard high-voltage linear regulators, making it particularly suitable for low-cost, low-power applications such as washing machines, central heating, power metering and similar applications that do not require galvanic isolation. The VB409 is highly efficient and has low internal power consumption. The package can use Surface Mount Technology PowerSO10(TM) or PENTAWATTHV (high voltage version) with through-hole mounting technology.
Manufacturing process and conduction angle control technology are two main features of VB409. This device is manufactured using the patented VIPowerM1 smart power technology developed by ST. In addition, ST also has multiple “vertical smart power†technologies. In this technology, a high-intensity bipolar or DMOS vertical power supply stage (current image In the discrete power transistor, the same DC body silicon) as the analog and digital circuits on the chip provide control, diagnostic and protection functions.
This technology started as large-scale production as early as the 1990s and has been widely used in the automotive field. Compared with automobiles and home appliances, the application environment is even worse, which proves the reliability of the technology. In addition to its inherent reliability, the number of external components required by the VB409 is also reduced, which further improves the overall reliability of the system.
The second feature of the VB409 is the technique it uses to convert the rectified AC input voltage to a 5V output voltage. Internal power consumption determines the maximum current that can be supplied without a heatsink, or the size of the heatsink required to supply a specified output current (the corresponding cost). Therefore, various voltage regulators are designed. An important issue to pay attention to. In offline regulator technology, the input is the AC supply voltage, but the output voltage is very low, only a few volts, the huge differential pressure between the input and output means that the efficiency is particularly important.
The VB409 has two separate stages, each connected to an external capacitor for storing electrical energy. The first stage is a pre-regulator, which is responsible for reducing the rectified high-voltage power supply to low voltage while charging the capacitor. The capacitor stores power during each AC power cycle, and then powers the second stage, low voltage linear regulator.
The pre-regulator uses a bipolar "Trilinton" passive device and three comparators. The first comparator measures the voltage on the integrated resistor and performs the internal current limiting function; the second comparator is responsible for the divided voltage of the rectified power input (determined by the external resistor divider) and the preset reference voltage In contrast, the third one is responsible for detecting the voltage on the capacitor. When the voltage at the midpoint of the resistor divider is below the threshold (eg, the conduction angle is less than the cutout value), the internal limiting current charges the capacitor. After the voltage on the capacitor reaches the maximum internal fixed value, the third comparator immediately acts to limit the current to the load requirement. When the conduction angle limit is reached, the input voltage level is switched to a high-impedance state, stopping the power absorption from the power supply. Since the VB409 only draws power from the power supply during the low-voltage portion of each positive cycle, the first-level power consumption is greatly reduced compared to the topology technology that continuously draws power from the power supply.
Of course, in order to ensure proper operation of the VB 409, the external capacitor must be charged during charging, and can be supplied to the second stage when offline. To ensure the functionality of the second stage at the maximum output current value, when selecting the capacitor value, the voltage on the capacitor must be greater than the rated minimum value, which is the sum of the output voltage and the minimum voltage drop on the second stage. Important parameters include the capacitance of the external capacitor and the ratio of the resistor divider. This topology allows the designer to use the capacity and cost of the external capacitor to solve the power consumption problem (heat sink volume and cost).
The maximum value of the external capacitor pre-regulator is 16V (typical). This pre-regulator can also supply the second load (such as a relay) that does not require excessive voltage regulation. Therefore, the VB409 can also be called double. Output regulator.
In a linear regulator, for a specified output voltage, the internal power dissipation is a function of the average input voltage: Pdiss = Iout(Vin - Vout), where Vin represents the average input voltage over a full cycle of the AC power supply. average value. For the VB409, as long as the preset conduction angle is exceeded (for most parts of the current cycle), the input current is negligible, and accordingly, the power consumption is correspondingly greatly reduced.
For example, when the average input voltage is 175V (equivalent to a 230V European grid power supply) and the output current is 25mA, the internal power dissipation should be (175-5) x 0.025 approximately equal to 4.4W when using a standard voltage regulator. With a VB409, an external 100uF capacitor, and a resistor divider ratio that guarantees correct operation, the internal power dissipation measurement is only 0.9W, which is even lower than one-quarter of the normal value!
Inductor and output pin in series, as shown in Figure 3, can further reduce the VB409's power consumption.
The series inductance removes the power switch coupling from the power supply, allowing the switch to operate in the saturation region when it is turned on. With this configuration, power consumption is reduced by 25% compared to a standard topology without an inductor. Diode D creates a discharge path for the energy stored in the inductor, limiting the overvoltage on the device when it is turned off.
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