摘要:
A bearing assembly includes a tube (30) axially defining an inner hole (32), a radial bearing (10) fixed in the inner hole of the tube and having an inner bearing surface concentric with the inner hole, and a shaft (20) pivotably received the inner hole. The shaft comprises a contact portion (22, 220) circumferentially formed at an outer periphery thereof confronting with the inner bearing surface of the bearing. The contact portion comprises an outer bearing surface being configured to have a substantially same abrasive resistance with the bearing surface to reduce wear thereon.
摘要:
A rubber extruder includes a barrel, a screw rod extending into the barrel, a threaded member threadedly engaging the screw rod and rotatable relative to the screw rod, a limiting member for limiting rotation of the screw rod upon rotation of the threaded member so as to permit axial movement of the screw rod, and a driving unit for rotating the threaded member.
摘要:
A clip (10) includes a body (12) including spaced first and second end portions, a first locking part (20) extending from the first end portion for attaching to a heat sink (80), and a second locking part (30) extending from the second end portion for attaching to a circuit board (50). The first locking part includes a pin (21), a pair of C-shaped spring portions (22), and a compressible mounting portion (23). The spring portions and the mounting portion are for cooperatively sandwiching the heat sink therebetween. The second locking part includes a taper head (30) and a neck (31). The second locking part engages with the circuit board in the neck. The first locking part offsets from the second locking part in a vertical direction. The heat sink of which the mounting holes offset from the mounting holes of the circuit board is therefore fitable to the circuit board.
摘要:
A hysteretic mode LED driver for providing a driving current for an LED includes a hysteretic comparing circuit and a feedback loop. The hysteretic comparing circuit compares a driving current related sensing signal with a reference signal to control the average value of the driving current. The feedback loop senses the error between the average value of the driving current and a target value to adjust the reference signal or the offset of the hysteretic comparing circuit to adjust the average value of the driving current.
摘要:
The present invention discloses a constant on-time switching regulator, a control method therefor, and an on-time calculation circuit for calculating an on-time period of a constant on-time switching regulator. The on-time calculation circuit calculates on-time according to practical conditions. It includes: a driver gate receiving a gate signal of a power switch in a switching regulator, the driver gate operating between high and low levels of a first reference voltage and ground; a low pass filter receiving an output from the driver gate and generating a second reference voltage, a ratio between the second reference voltage and the first reference voltage being substantially the same as a duty ratio of the gate signal; and an on-time generator comparing the second reference voltage with a ramp signal to determine an on-time of the power switch.
摘要:
An electronic device includes a circuit board and a heat sink . A heat generating part is located on the circuit board. Through holes are defined in the circuit board. The heat sink includes a main body and resilient pieces located on the main body. The resilient pieces includes a latching portion and a resisting portion located on the latching portion. The latching portion extends through the through hole to engage with the circuit board. The resisting portion is received in the through hole and abuts the circuit board. The main body closely abuts the heat generating part. The latching portion can be disengaged from the circuit board simply by squeezing the resisting portion.
摘要:
An electronic device includes a bottom plate, a cover plate, a dust collection box, and a dust cleaning apparatus. A heat sink is mounted in the bottom plate. The cover plate covers on the bottom plate. The cover plate defines a cutout. The dust collection box is placed on the bottom plate via the cutout. The dust cleaning apparatus is slidably mounted on the bottom plate. The dust cleaning apparatus moves relative to the heat sink to sweep dust of the heat sink into the dust collection box.
摘要:
The present invention discloses a fuse circuit for final test trimming of an integrated circuit (IC) chip. The fuse circuit includes at least one electrical fuse, at least one control switch corresponding to the electrical fuse, and a resistant device. The electrical fuse is connected with the control switch in series between a predetermined pin and a grounding pin. The control switch receives a control signal to determine whether a predetermined current flows through the corresponding electrical fuse and breaks the electrical fuse. The resistant device is coupled between a bulk terminal and a source terminal to increase a resistance of a parasitic channel, such that an electrostatic discharge (ESD) protection is enhanced, and errors of final test trimming of an IC chip are avoided.
摘要:
A heat dissipation device includes a centrifugal fan and a fin assembly aside the centrifugal fan. The centrifugal fan includes a casing and an impeller received in the casing, the casing defines an air outlet at one side thereof. The fin assembly is located at the air outlet of the centrifugal fan. The fin assembly includes a plurality of fins parallel to and spaced from each other. Each of the fins includes a main body and an extending portion extending form the main body toward the air outlet of the centrifugal fan. Each extending portion includes a side edge facing the air outlet of the centrifugal fan, the side edge is arc shaped and inwardly concaved toward the main body.
摘要:
The present invention discloses a constant on-time switching regulator, a control method therefor, and an on-time calculation circuit for calculating an on-time period of a constant on-time switching regulator. The on-time calculation circuit calculates on-time according to practical conditions. It includes: a driver gate receiving a gate signal of a power switch in a switching regulator, the driver gate operating between high and low levels of a first reference voltage and ground; a low pass filter receiving an output from the driver gate and generating a second reference voltage, a ratio between the second reference voltage and the first reference voltage being substantially the same as a duty ratio of the gate signal; and an on-time generator comparing the second reference voltage with a ramp signal to determine an on-time of the power switch.