In recent years, the application fields of high-brightness LEDs have been increasing, covering a wide range from mobile device backlights, medium and large-size LCD backlights, automotive interior and exterior lighting, and general lighting. Common DC-DC LED lighting applications include landscape lighting, internal low-voltage road lighting, solar-powered lighting, automotive lighting, applied vehicle lighting, marine applications, low-voltage halogen replacement, and aircraft interior lighting.
ON Semiconductor provides multiple LED drivers for DC-DC low-power LED lighting applications, covering different topologies such as boost, buck, and buck-boost, as shown in Figure 1. In this series of products, NCL30160 and NCL30161 are two newer DC-DC LED drivers from ON Semiconductor. The NCL30161 LED driver is suitable for wide voltage applications. It can control the LED ripple current at 10% of the average current through average current control. The output does not require a filter capacitor and supports PWM or analog dimming; there is also a converter NCL30160 integrated MOSFET can also minimize space and cost. This article will focus on the key features and application design points of these two products.
Figure 1: ON Semiconductor's DC-DC LED driver selection decision chain.
Advantages and typical applications of NCL30161
NCL30161 is an average current hysteresis control mode high brightness LED buck controller. Because the LED ripple current is effectively controlled, the output does not require a filter capacitor; for work at frequencies up to 1.4 MHz, small-size passive components can be used on the periphery; the voltage is provided to the chip through an external resistor or linear buck, which can support high-voltage input ; Support pulse width modulation (PWM) or analog dimming. Analog dimming simply adjusts the DC current of the LED string to change the light output of the LED; while PWM dimming is to change the duty cycle of the constant current in the LED string to effectively change the average current in the LED string to achieve dimming Light.
The NCL30161 has many features, such as Vin input voltage range of 6.3 V to 40 V, which can be externally expanded to a higher input voltage; LED current can be set by an external resistor and can work at 100% duty cycle; the controller does not need to be Loop compensation, hysteresis control can achieve good power injection suppression and fast load transient response; when there are multiple strings of LEDs (such as RGB), the ground current detection can use multiple strings of LEDs such as RGB common anode connection to reduce LEDs Number of strings; single pin to achieve PWM dimming and enable control, wide dimming range; support output full ceramic capacitor or no output capacitor design, use small external components, save space and cost; perfect protection function Including adjustable LED current, LED short circuit protection and input undervoltage protection, and overheat protection.
Due to the use of very few external components, NCL30161 is an ideal solution for automotive, industrial, and general lighting. Markets and applications include LED drivers, constant current sources, automotive lighting, general lighting, and industrial lighting.
Figure 2: NCL30161 typical application buck LED driver
Figure 2 is a block diagram of a typical application buck LED driver for NCL30161. It can be seen that the LED is directly connected to the input voltage, and the current is set by the RSENSE connected to the ground; PWM dimming and enable control are realized through the DIM / Enable pin of the chip; ROT is used to set the initial off time.
This is an average current hysteresis control inverted Buck topology. The external MOSFET can realize high current LED driving. The continuous current mode does not require an output capacitor; the operating frequency is up to 1.4 MHz, which can be adjusted by an external inductor.
Figure 3 is the internal block diagram of NCL30161, which is composed of 7 parts: the internal LDO part changes the input high voltage to 5 V voltage regulation, powers the internal logic, including external MOSFET drive; PWM dimming and enable control part; MOSFET Drive part; internal comparator peak current detection part, the comparison voltage is 220 mV; valley current detection, internally set at 180 mV; LED short circuit detection; turn-off time adjustment.
Figure 3: Internal block diagram of NCL30161
The control logic of the NCL30161 is as follows. By detecting the peak and valley currents of the LED, the hysteresis control of the LED current can be realized. The ripple current of the LED is controlled within ± 10% of the average current. Current, the average LED current is constant, and does not change with the input voltage and the number of LEDs in series. When the MOSFET is turned on, when the LED current increases to reach a peak current of 220 mV, the MOSFET is turned off; when the MOSFET is turned off, the LED current drops, and the internal off-time timer determines the off-time, when the timing time is reached, the valley current is detected when the MOSFET is turned on The next turn-off time is adjusted according to the detected valley current, and the valley current is controlled at 180 mV in steady state.
Military battery has a wide application on some high-tech euquipment including military communications equipment, submarine, drone , warship, government and so on .
The design for Military Battery Pack is more strict than normal lithium or Lipo Battery packs ,because it must meet some tough requirements as ;
1, high-level safety : military Lithium Battery was demanded to provide high-level safety and will not cause any death or accident with High intensity impact and and hit.
2, high reliability: the Military Battery must be reliable and could not causing any problems to the equipments during operating .
3, High environmental adaptability: the military Battery Pack is demanded to use in different temperature ,air pressure and other enviornmental condition.
Military Batteries : Ni-Mh Battery Pack BB-390/U
Besides ,the military always have a strict standard on low power self-consuming and deep life cycles .so these above standard has made it special from the other Lithium Battery Pack or other battery packs which applied to life .
Military Batteries
Military Batteries,Military Battery,Military Vehicle Battery,Military Solar Battery
YFJ TECHNOLOGY (HK) CO.,LIMITED , http://www.yfjpower.com