According to the principle of the transformer, the total energy transmitted can only be reduced not higher than the input, so under the condition of a certain transmission power, the higher the output voltage, the smaller the output current.
5V booster to 12V chip must have the maximum output power or output current label, such as output 12V1A or output 12W, so in use must be careful not to exceed the calibration range, otherwise it will lead to 5V power supply current is too large and failure.