PIC16C717T-E/SS【PDF 8/220 页】IC MCU OTP 2KX14 A/D PWM 20SSOP

收藏本站

您好，
买卖IC网欢迎您。
请登录
免费注册

买卖IC网

Sheet目录3890

4页 5页 6页 7页 [8页]9页 10页 11页 12页

2002 Microchip Technology Inc.

DS41120B-page 103

PIC16C717/770/771

10.1

Bandgap Voltage Reference

The bandgap module generates a stable voltage refer-

ence of over a range of temperatures and device sup-

ply voltages. This module is enabled anytime any of the

following are enabled:

Brown-out Reset

Low-voltage Detect

Either of the internal analog references (VRH,

VRL)

Whenever the above are all disabled, the bandgap

module is disabled and draws no current.

10.2

Internal VREF for A/D Converter

The bandgap output voltage is used to generate two

stable references for the A/D converter module. These

references are enabled in software to provide the user

with the means to turn them on and off in order to min-

imize current consumption. Each reference can be indi-

vidually enabled.

The VRH reference is enabled with control bit VRHEN

(REFCON<7>). When this bit is set, the gain amplifier

is enabled. After a specified start-up time a stable ref-

erence of 4.096V nominal is generated and can be

used by the A/D converter as a reference input.

The VRL reference is enabled by setting control bit

VRLEN (REFCON<6>). When this bit is set, the gain

amplifier is enabled. After a specified start-up time a

stable reference of 2.048V nominal is generated and

can be used by the A/D converter as a reference input.

Each voltage reference is available for external use via

VRL and VRH pins.

Each reference, if enabled, can be output on an exter-

nal pin by setting the VRHOEN (high reference output

enable) or VRLOEN (low reference output enable) con-

trol bit. If the reference is not enabled, the VRHOEN

and VRLOEN bits will have no effect on the corre-

sponding pin. The device specific pin can then be used

as general purpose I/O.

FIGURE 10-1: BLOCK DIAGRAM OF LVD AND VOLTAGE REFERENCE CIRCUIT

Note:

If VRH or VRL is enabled and the other ref-

erence (VRL or VRH), the BOR, and the

LVD modules are not enabled, the band-

gap will require a start-up time before the

bandgap reference is stable. Before using

the internal VRH or VRL reference, ensure

that the bandgap reference voltage is sta-

ble by monitoring the BGST bit in the LVD-

CON register. The voltage references will

not be reliable until the bandgap is stable

as shown by BGST being set.

VDD

generates

BGAP

VRH

VRL

LVDEN

LVDCON

REFCON

BODEN

LVDEN

VRHEN + VRLEN

RA1/AN1/LVDIN

LVDIF

发布紧急采购，3分钟左右您将得到回复。

采购需求

(若只采购一条型号，填写一行即可)

*型号	*数量	厂商	批号	封装

添加更多采购

采购需求

发布成功！您可以继续发布采购。也可以进入我的后台，查看报价

发布成功！您可以继续发布采购。也可以进入我的后台，查看报价

我的联系方式