The ultraviolet bacteria box uses ultraviolet rays to murdered bacteria, and UV LEDs produce ultraviolet rays of 260 nm to 280 nm, directly cutting off bacteria DNA / RNA, thoroughly killing bacteria, and the bacteria is as high as 99%. LED ultraviolet sterilization technology, earliest application in American aerospace disinfection, now gradually applied to daily life, LED strong UV energy can decompose odor molecular structure, effectively remove the mold of cosmetics, glasses, watches and other objects. It can be used in the sterilization of baby supplies, and daily items are disinfected.
TI provides a system solution for ultraviolet kit, and the principle block diagram is as follows.
Figure 1: System block diagram of ultraviolet bactericidal box (no battery version)
Figure 2: System block diagram of ultraviolet bactericidal box (with battery version)
Power supply plan
The UCC2891X series is a FlyBack controller that uses FM + amplitude mixed control, integrated 700V MOSFET, support 85-265VAC bus voltage. Among them, the UCC28910 can achieve a 9.5W output power, and the UCC28911 maximum can achieve 12W output power.
The advantages are as follows:
1. Low-load low frequency work to improve efficiency;
2. MOSFET is opened in the trough to reduce switch loss;
3. Two modes with constant voltage output and constant current output;
4. The maximum switching frequency is 115kHz, and EMC performance is improved by jitter frequency;
5. Perfect protection characteristics: AC bus protection, output overvoltage protection, over temperature protection, short circuit protection
6. Adopting the original feedback method, the optocoupler and TL431 can be reduced, and ± 5% V / I adjustment accuracy can be achieved;
7. No external current detection resistance is required;
8. You can implement system standby power consumption of 30 mW;
9. There is almost noise;
Figure 3: System block diagram of TIDA-00473
TLV742P is a very cost-effective linear regulator that supports wide voltage range output, excellent performance, which is ideal for 5V and below the voltage range system. The TLV742P series can be applied directly to a single lithium ion battery system, and the input output voltage is reduced to 0.85V. TLV742P has active output discharge functions to help ensure low output in system disabling, standby mode, or sleep mode. In addition, overcurrent protection is used to protect the equipment in the event of a short circuit and a hot shutter to prevent overheating.
Figure 4: TLV742P simplified schematic
The TLV704 series low-pressure difference linear regulator has a very low static current, suitable for power saving applications. In full load range and full temperature range, the static current is almost unchanged. For low power MCUs, such as MSP430, this device is an ideal power management device. The input voltage range of TLV704 is 2.5V to 24V, so that the device is applicable to battery-powered applications, and is applicable to industrial applications that have large surge surges.
Figure 5: TLV704 Simplified Schematic
Charging plan
BQ25619 is a highly integrated 1.5A battery charging management and system power path management device for single-cell lithium ion and lithium polymer batteries. The input voltage ranges from 3.9V to 13.5V, which is suitable for a variety of applications. The input reverse block FET (RBFET, Q1), high-side switch FET (LSFET, Q3), low-side switch FET (LSFET, Q3), and the bootstore diode are simplified. system design. BATFET on-resistance is only 19.5mΩ, low impedance power path optimizes operation efficiency, shortening battery charging time and extends battery run time during the discharge phase. 5V input, 1A charging current, charging efficiency can reach 94%. The factory model has only 3μA current consumption, ensuring that the battery is full, and the I2C interface with charging and system setting makes it a real flexible solution.
Figure 6: Simplified schematic of BQ25619
Compared to BQ25619, BQ25616 is a stand-alone battery charging manager, the maximum charge current is 3A, and the charging speed is faster.
Figure 7: BQ25616 Simplified Schematic
BQ2970 provides protection for lithium ion / lithium polymer batteries, and monitors external power MOSFET to provide protection, including overter protection, overprofake protection, charge and discharge overcurrent protection, short-circuit detection. The current consumed in the normal mode runs only 4μA, reducing the battery consumption of the battery. The size is only 1.5mm * 1.5mm * 0.75mm, which is conducive to reducing the volume of the battery pack.
Figure 8: Simplified schematic of BQ2970
LED driver
High performance RGB LED drivers are essential in other applications of smart home and with human machine interaction. LED animation effects (such as flashing, breathing, and chasing) can greatly improve user experience while minimizing system noise is also critical.
The LP5012 is a 12-channel constant current trap LED driver. LP5012 includes integrated color mixing and brightness control, and pre-configured features simplify software encoding processes. The integrated 12-bit, 29kHz PWM generator is full, vivid, and eliminated the tonary noise for each channel. Each LED is independently controlled to help achieve smooth dimming effects. Independent color mixing and brightness control registers make software coding very simple. When the respiratory effect of the fade-in fade out is, the global R, G, and B group control can significantly reduce the MCU load. The LP5012 can also implement PWM phase shift to help reduce input power when multiple LEDs are simultaneously open. The LP5012 can implement automatic energy saving mode to achieve ultra-low static current. When all channels turn off 30ms, the total power consumption of the device will drop to 10μA, which makes the LP5012 device becomes a potential choice for battery power supply terminal devices.
Figure 9: LP5012 Simplified Schematic
TPS61169 is a boost LED drive, an interior integrated 40V, 1.8A MOSFET, a single LED or LED string for small or large panel backlighting. The default white LED current is set through the external sensor resistor Rset, and the feedback voltage is stabilized to 204mV. During operation, the LED current can be controlled by the pulse width modulation (PWM) signal applied to the CTRL pin, the duty ratio of the signal determines the feedback reference voltage. TPS61169 does not burst out the LED current, so it does not generate a smellable noise on the output capacitor. To provide optimal protection, the device integrates the LED open protection characteristics, which disables TPS61169 in the LED open state to prevent the output voltage excess the maximum absolute rated voltage of the IC.
Figure 10: TPS61169 Simplified Schematic
Main control program
MSP430FR211X This ultra low power consumption, low-cost MCU has a powerful 16-bit RISC CPU, providing 2kb ~ 4kb FRAM and 1KB SRAM. The serial interface has a UART and IRDA or SPI, integrated with 6-bit DAC and 8-channel 10-bit ADC, with 12 GPIO ports, and its low power consumption and QFN24 (3 * 3mm) package are extremely suitable for portable devices.
Figure 11: Interior resources of MSP430FR211X
Audio solution
The TPA6203A1 is a 1.25W mono all-in-band frequency amplifier with a power supply range of 2.5 V to 5.5 V, which can drive at least 8 Ω horn. The static current is only 1.7mA, the shutdown mode consumes 10 μA, 2mm * 2mm minimal package, and only 5 peripheral devices, which greatly saves the PCB board area.
Figure 12: TPA6203A1 Reference Schematic, Read Full Text Title: Ultraviolet Box TI Solution
Article Source: [Micro Signal: Tisemi, WeChat public number: China Site Electronics Design Circle] Welcome to add attention! Please indicate the source of the article.
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