Huntkey Jumper 300G Planet3dnow.de Edition Power Supply Review
Secondary Analysis
Contents
The Huntkey Jumper 300G Planet3dnow.de Edition uses a DC-DC design in its secondary, meaning that this power supply is basically a +12 V unit, with the +5 V and +3.3 V outputs being generated by two smaller switch-mode power supplies connected to the main +12 V output. This design is proving to be the best solution to achieve high efficiency. Also, this unit uses a synchronous design for the +12 V rectification. This means that the rectifying diodes were replaced with transistors in order to increase efficiency.
As briefly mentioned on the previous page, the +12 V rectifying diodes and the resonant controller are located on the same printed circuit board, which is located in the secondary of the power supply.
The +12 V output uses two IRFB3206 MOSFETs, each one capable of handling up to 210 A at 25° C or 150 A at 100° C in continuous mode, or up to 840 A at 25° C in pulse mode, with a maximum RDS(on) of only 3 mΩ. That is a brutal overspecification!
Figure 15: +12 V transistors
As explained, the +5 V and +3.3 V outputs are generated through two separate switch-mode power supplies, which are available as two add-on modules. Each power supply uses an APW7073 PWM controller and two IPD036N04L MOSFETs, each supporting up to 90 A at 25° C or 87 A at 100° C in continuous mode or up to 400 A at 25° C in pulse mode, with a maximum RDS(on) of 3.6 mΩ.
Figure 16: One of the DC-DC modules
Figure 17: One of the DC-DC modules
This power supply uses a WT751002 monitoring integrated circuit. This is a very basic chip, supporting only over voltage (OVP) and under voltage (UVP) protections, and it doesn’t monitor the +12 V output for UVP. An AS339 voltage comparator creates the over current protection (OCP) circuit.
Figure 18: Monitoring circuit
This power supply uses two solid capacitors and three electrolytic capacitors from Fcon to filter the +12 V output. The +5 V and +3.3 V outputs are filtered using solid capacitors, as you can see in Figure 16.