A system and method of operating an integrated circuit (IC) having a fixed layout of one or more blocks having one or more current sources therein that draw electrical current from a power source. The method includes dynamically issuing to a block configured to perform operations responsive to an instruction received at the block, a reserve amount of tokens; determining for each issuance of instruction to the block whether that block's reserve token amount exceeds zero; and one of: issuing the instruction to the block if the token reserve for that block is greater than one, and decrementing, after issuance of the instruction, by one token the block's reserve token amount, or, preventing issuance of an instruction to the block. In the method, each block may be initialized to have: a reserve token amount of zero, a token expiration period; a token generation cycle and a token generation amount.