In the past few years Silicon Photo-multiplier (SiPM) has emerged as a new detector in various applications due to its promising characteristics for low light detection. However SiPM has certain limitations out of which temperature dependence of gain is an important parameter which limits the application fields to temperature controlled or indoor environment. Change in temperature changes the breakdown voltage and hence the gain; therefore the biasing voltage needs to be trimmed according to temperature for maintaining the constant gain. This paper explores different power supply techniques that have been used for SiPM. Many commercial power supplies are compared and different approaches which are tried by various research groups for maintaining stable gain are discussed.