Circuit and method for adjusting bus pull-up voltage according to pull-up voltage of slave device

Abstract

The invention discloses a circuit and a method for adjusting the pull-up voltage of a bus according to the pull-up voltage of a slave device. The circuit includes a bus, a voltage dividing unit, a comparator, a latch and an impedance unit, wherein: the voltage dividing unit divides the voltage output by the first power supply to obtain the divided voltage; the first input terminal of the comparator receives the divided voltage The second input terminal of the comparator receives the pull-up voltage from the device through the bus, and the output terminal of the comparator outputs the comparison result; the first input terminal of the latch receives the comparison result, and the second input terminal of the latch receives the A trigger signal, the output terminal of the latch outputs a control signal to control the resistance value of the pull-up resistor connected to the bus by the impedance unit, so that the pull-up voltage formed by the pull-up resistor of the bus is equal to the pull-up voltage of the slave device to achieve voltage matching . Through the above method, the present invention can automatically increase the pull-up voltage on the bus according to the working voltage of the slave device, thereby realizing voltage matching.

Description

technical field [0001] The invention relates to the technical field of power supplies, in particular to a circuit and a method for adjusting the pull-up voltage of a bus according to the pull-up voltage of a slave device. Background technique [0002] At present, AC-DC (alternating current-Direct Current) power modules for rack servers have various power types such as 750W, 800W, and 1200W, and there are different suppliers. Among them, 750W and 1200W are from one manufacturer, and 800W is from another manufacturer. The pull-up power of the communication interface IIC (Inter-Integrated Circuit) of the 750W and 1200W power modules is 5V, the pull-up resistor is 20K, and the pull-up power is integrated inside the power module. The pull-up power of the communication interface IIC of the 800W power module is 3.3V, the pull-up resistor is 20K, and the pull-up power is integrated inside the power module. The device data of the power module clearly requires that a pull-up resisto...

AI Technical Summary

Problems solved by technology

The pull-up of the IIC is directly implemented on the hardware, and it is impossible to intelligently switch between the voltages of the two power supplies according to the type of the power module.

If a server needs to be compatible with power modules from two manufacturers, the hardware design cannot be compatible

Some server products are forced to remove a power module in the specifications because they cannot be compatible with each other, such as the compatibility of 800W power modules, which will reduce the applicability of server power modules

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