The no-load power consumption of LED drive power is the power consumed when the power load is open and does not perform any function. Standby power consumption is the amount of power consumed when the power supply is in standby mode, when it goes into hibernation mode and stops supplying power to the load, allowing only small amounts of power to be supplied to small loads (such as the CPU in the TV chair) under special circumstances. According to the IEC16301 standard (section 4.5) formulated by the international electrotechnical commission, the no-load power consumption and standby power consumption of LED drive power should both be lower than 5mW, which puts forward more stringent conditions for the design of LED drive power.

The method of eliminating power loss of discharge resistor after starting up
The series mode capacitance in EMI filters, also known as X capacitance, is located between the two input ends of the power supply and is used to filter out the power supply noise. Because Ⅹ capacitors to store high voltage charge after the ac power is still, once the user get an electric shock source plug will pose a security threat. The solution is to discharge a discharge resistor in parallel to the X capacitor in order to meet the safety requirements. However, the disadvantage of this scheme is that when the LED drive power supply is working normally, the discharge resistance will produce constant power loss, leading to a decrease in power efficiency. The resistance range of discharge resistance R is usually 150kg~ 1.5mg, corresponding to 220V ac. The power loss on R is as high as 48-323mw, which has far exceeded the maximum limit of 5mW. Therefore, effective measures must be taken when designing EMI filters to greatly reduce the power loss of discharge resistance.
In April 2010, PI introduced a new self-powered CAPZero series X with two terminals
Capacitor zero loss discharger integrated circuit. It requires no external bias circuit and can be extremely high without grounding
The ability to suppress common mode interference and cross mode interference. Zero loss discharger Ⅹ capacitance can be equivalent to intelligent high voltage switch S, keep it open in normal working conditions in LED drive power supply, by cutting off discharge resistance on the current, make the resistance power loss is close to zero. Even considering that MOSFET's off resistance is not infinite, the power loss of the discharge resistance can be reduced to less than 5mW, which is close to zero loss and fully meets the provisions of IEC16301 international standard. When ac power, the device can quickly will discharge resistor connected, automatic to safe discharge of Ⅹ capacitance, and allows the use of more large capacity Ⅹ capacitance, without any increase in standby power consumption. It works with A current of only 21.7 microns and A maximum ambient temperature of +105 ° c. X zero loss Ⅹ discharger for capacitors (greater than l0 omega nF) and requires very low standby power loss of ACDC converters. Internally integrated with two 825V(or 1000V) MOSFET, it can meet the design needs of various LED driver power supply, suitable for PC, server, TV, printer and laptop switching power supply, as well as power adapter with very low no-load power loss.
Ⅹ zero capacitance loss discharger typical application in EMI filter as shown in figure 93-1, figure is omitted in the common-mode capacitance (also called Y capacitor, which is used to inhibit common-mode interference) such as Qi device. R1 and R2 are external discharge resistances with a total resistance of R. C1 and C2 for Ⅹ capacitance.