In Switched Mode Power Supply , which is adjusted by setting the minimum duration of DCM operation, the SMPS selectively operates in continuous current mode (CCM) and discontinuous current mode (DCM) with a minimum switching frequency. The resistance value applied to the external pin of the SMPS is activated when entering the DCM while controlling the duration of the timer reset in the CCM. At the variable duration cutoff, the led switching power supply returns to the CCM for at least one switching cycle. This allows the smps power supply minimum effective switching frequency to be set for each application deploying the SMPS at a level that avoids audible noise, thereby maximizing the efficiency of the DCM operating under light load conditions. SMARTS POWER SUPPLY relates to the field of switch mode power supplies, and more particularly to mini power supply with variable minimum switching frequencies.
By operating in "discontinuous conduction mode" (DCM) under certain load conditions, SMPS can increase overall efficiency. Because the SMPS effectively turns off its switching output and allows the load to "float." The CCM operation can be re-entered in response to, for example, the value of the output voltage. At light loads, the SMPS can operate primarily in the DCM, entering the CCM relatively infrequently, and the effective switching frequency can be reduced to less than 20 kHz, which is within the human hearing range (approximately 20 Hz to 20 kHz). In some applications, SMPS output switching can cause mechanical vibrations in one or more circuit components, creating annoying audible noise. One way to eliminate this possibility is to limit the minimum switching frequency to a value within the ultrasonic range, such as 25 kHz or higher. However, this limits the efficiency benefits that DCM can achieve by operating at frequencies below the ultrasonic waves under light load conditions.
On the one hand, the SMPS includes an adjustment circuit configured to selectively operate in a discontinuous conduction mode (DCM) and a continuous conduction mode (CCM). The SMPS also contains a timer that is activated when the regulation circuit enters the DCM and indicates a variable duration. The SMPS additionally contains a control circuit configured to monitor the output voltages of the switched mode power supply circuit and the timing circuit during DCM operation of the regulating circuit and to restore the regulating circuit to CCM operation in response to an earlier arrival of the output voltage. Defined voltage limit or duration.
On the other hand, the SMARTS POWER SUPPLY switch mode power supply is selectively operated in a continuous conduction mode (CCM) and a discontinuous conduction mode (DCM) to regulate the output voltage. Monitors the current in the switching circuit inductor associated with the output voltage. In response to detecting a zero or negative inductor current, the SMPS switches from CCM to DCM operation. The output voltage is monitored and is responsive to detecting that the output voltage is equal to or lower than a reference voltage level. For example, led power supply 12v dc switches from DCM to CCM operation. The time at which the led led driver 12v is operating in the DCM is monitored and switched from DCM to CCM operation after a variable operational duration in the DCM.
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