A pressure switch for controlling application of negative pressure to dressing disposed adjacent a tissue site is disclosed. The pressure switch comprises a body having a base, sidewalls extending from the base to an open end, and an inlet coupled to the dressing and forming a passage through the body. The pressure switch further comprises a diaphragm closing the open end of the sidewalls and forming a vacuum chamber with the body, wherein the inlet fluidly couples the vacuum chamber and the dressing. The pressure switch further comprises a valve disposed in the passage and configured to restrict the flow of gas through the passage so that a switch pressure developed in the vacuum chamber as a result of the application of negative pressure to the dressing lags a wound pressure at the tissue site to delay, wherein the diaphragm is adapted to be operatively responsive to the switch pressure to move between a relaxed position and a compressed position as the negative pressure increases and decreases. This pressure switch further comprises a switching element coupled to the diaphragm to turn on the negative pressure in the relaxed position and turn off the negative pressure in the compressed position. In another example, a method for controlling application of negative pressure to dressing disposed adjacent a tissue site using a pressure switch is disclosed. In another example, a system for applying negative pressure to a tissue site using a pressure switch is disclosed.Linvention concerne un commutateur de pression pour réguler lapplication de pression négative sur un pansement adjacent à un site tissulaire. Le commutateur de pression comprend un corps ayant une base, des parois latérales sétendant de la base jusquà une extrémité ouverte et une entrée couplée au pansement et formant un passage dans le corps. Le commutateur de pression comprend également un diaphragme fermant lextrémité ouverte des parois latérales et formant une chambre à vide avec le corps, lentrée co
