Based on PT6913 non-isolated high voltage LED driver IC solution

　　The PT6913 chip uses a linear constant current to control the output current. It has an internal integrated power MOS, and the output current can be set to 10mA~60mA through an external resistor. The maximum input voltage of the PT6913 can reach 400V, and it uses a high-end drive method to provide LED open circuit and LED short circuit protection. In any case, the excess voltage of the input power supply that is higher than the LED load is borne by the PT6913, and the LED load will not face the threat of overvoltage, which provides very high reliability and stability for the overall solution.

　　In order to prevent the IC from overheating and damage, PT6913 integrates a temperature compensation function. When the internal junction temperature of the IC rises to 130℃, PT6913 begins to reduce the output current. When the junction temperature reaches 150℃, the output current will be reduced to 0. This can avoid the flickering problem of traditional over-temperature protection methods.

　　How it works

　　PT6913A/B adopts linear constant current drive technology, and the circuit topology is simple and practical. The LED load, chip and rectified power supply are connected in series to form a current loop, and the output current is set by the IC. When the input voltage is higher than the LED load voltage, the output current is constant. The input voltage exceeds the LED load voltage and is borne by the IC. The maximum input voltage of the IC can reach 400V, which meets most AC input applications.

　　Program Features

　　◆ 5V~400V working voltage

　　◆ Output current can be set from 5 to 60mA

　　◆ ±5% output current accuracy

　　◆ Multiple ICs can be used in parallel to meet the needs of larger current output

　　◆ High power factor

　　◆ High efficiency

　　◆ Very few peripheral components

　　◆ No electrolytic capacitor required

　　◆ LED open circuit and short circuit protection

　　◆ Temperature attenuation function

　　◆ - TJ>130℃, the output current starts to decrease; - TJ>150℃, the output current decreases to 0

　　Temperature decay

　　PT6913A/B integrates temperature attenuation function. When the internal junction temperature of IC is higher than 130℃ (typical value), the IS pin voltage decreases at a coefficient of 15mV/℃, and the output current also decreases accordingly. When the internal junction temperature of IC reaches 150℃, the output current will be reduced to 0.

　　The temperature attenuation function can effectively avoid the flickering phenomenon caused by the traditional overheat protection function. When the abnormal ambient temperature causes the IC junction temperature to rise and reach 130°C, the PT6913A/B will try to reduce the LED heat by reducing the output current, thereby reducing the ambient temperature. The output current and the ambient temperature will likely reach a balance, which is different from the traditional overheat protection mechanism (for example: when the IC junction temperature reaches 150°C, the IC is turned off, and when the IC junction temperature drops by 20°C, the IC resumes working), thus avoiding LED flickering.

　　LED short circuit protection

　　PT6913A/B adopts linear constant current control mode. The excess voltage of input voltage higher than output voltage is borne by IC. IC input voltage can reach 400V. When some LEDs are short-circuited, the voltage borne by IC will increase, resulting in increased IC power consumption and IC temperature rise. If the internal junction temperature of IC is still less than 130℃, the output current will remain constant. The worst case is that the positive and negative ends of LED load are short-circuited, and all input voltages are borne by IC. The internal junction temperature of IC will rise sharply to 150℃, and IC will shut down output. Obviously, LED short-circuit protection is achieved through temperature attenuation.

　　Application

　　◆ LED bulb

　　◆ LED tube

　　◆ Compact LED lighting products

　　Typical application circuit

　　Typical performance evaluation